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Discussion Starter #1
Hi guys, thought I’d throw this up here since I couldn’t find any feedback before I purchased.
So I initially installed a mufflerless catback system on my Red Sport paired with the AMS lower downpipes. It was a big mistake for me. Thought I wanted loud, turns out I didn’t at all. I made it four miles down the road before I turned around and had the own muffler reinstalled with the AMS downpipes still. As effective as they were, I didn’t really care for the amplified turbo sound coming in cabin so I took a shot on the HKS.
Initial response was couldn’t be happier. If you want more power without sacrificing luxury, these are the way to go. They aren’t any louder in the slightest bit at cruise or wide open throttle. Sounds stock.
As far as build quality and fitment, I’d give them 5 stars. My installer rated the ease of install at 9 out of 10.
And lastly for performance, this was difficult for me to judge at first. I had them installed at the same time I was supposed to get an Ecutek tune. Unfortunately there was an issue on not having the right flash for my specific early year model, so I had downpipes installed but was down JB4 when I left. That was removed because I had it sold the next day. So needless to say I couldn’t compare it to before I brought it in so I am comparing to stock. It has definitely picked a lot in the low end. I’m getting wheel spin where I haven’t previously on stock boost levels. And most impressively to me is that partial throttle acceleration, like as used for lane changes. The car just floats effortlessly as the turbo spools quicker at lower rpms.
I’m a fan of the 2.5” over the competitors 3” variants. I’ll sacrifice a little horsepower for torque since the vast majority of my driving is not spent at wide open throttle. And IMO, 3” is overkill on these tiny turbos and my tuner agreed with that.
Again, couldn’t be happier with them. I should be getting the tune in the next week or two so I’ll be sure to update and post the dyno graph for all who are interested.
 

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Thanks for the detailed review and pictures. So it looks like these remove the secondary cats and replace with a resonator to keep the noise tame. Is that correct?
 

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Thanks for the review. Did you happen to obtain weights of the HKS DPs before install? What CB do you have?

I do still think the bang for the buck purchase is the Megan Racing DPs but it's good to have options. And, of course, the HKS are resonated. I'm not totally sure but I suspect noise output would be similar with resonators in either the DPs or the CB. Did you contemplate that combo? - Keeping your AMS DPs and going with a resonated exhaust?
 

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Discussion Starter #5
Thanks for the detailed review and pictures. So it looks like these remove the secondary cats and replace with a resonator to keep the noise tame. Is that correct?
Yes that is correct.
Im about to order these soon.

Question: are those stickers heat resistant or were just there during photo shoot?
Honestly not sure as I didn’t install personally. I’ll see next time I’m on a lift lol.
Thanks for the review. Did you happen to obtain weights of the HKS DPs before install? What CB do you have?

I do still think the bang for the buck purchase is the Megan Racing DPs but it's good to have options. And, of course, the HKS are resonated. I'm not totally sure but I suspect noise output would be similar with resonators in either the DPs or the CB. Did you contemplate that combo? - Keeping your AMS DPs and going with a resonated exhaust?
So the shipping weight was 16lbs. I did have the Ams downpipes on a resonated afe takeda mid/y pipe combo exiting out of the stock muffler. There was still a lot of cabin noise coming through. If sleeper is the goal, these are hands down the winner.
Right now, these are on stock catback. If Fast Intentions does a nice Black Friday sale, that may not be the case much longer.
All set for tune on this Friday so I’ll be sure to update with dyno.
 

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Awesome good luck. I have a Stillen CB awaiting install. I am nervous that it might be too loud with no resonators, fairly small mufflers, and my existing non-resonated MR LDPs. We shall see...
 

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So you are running lower down pipes with factory exhaust?

You get torque but no HP based on my past experience (different platform), and it may not be a good idea for your turbos long term.

It would be better to run a quiet catback and leave the factory downpipe.

Thanks for the review nonetheless. It is a quality piece.
 

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Yes that is correct.

Honestly not sure as I didn’t install personally. I’ll see next time I’m on a lift lol.

So the shipping weight was 16lbs. I did have the Ams downpipes on a resonated afe takeda mid/y pipe combo exiting out of the stock muffler. There was still a lot of cabin noise coming through. If sleeper is the goal, these are hands down the winner.
Right now, these are on stock catback. If Fast Intentions does a nice Black Friday sale, that may not be the case much longer.
All set for tune on this Friday so I’ll be sure to update with dyno.
Any reason you aren't waiting for the catback before the tune?
 

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Discussion Starter #9
So you are running lower down pipes with factory exhaust?

You get torque but no HP based on my past experience (different platform), and it may not be a good idea for your turbos long term.

It would be better to run a quiet catback and leave the factory downpipe.

Thanks for the review nonetheless. It is a quality piece.
Any reason you aren't waiting for the catback before the tune?
Yes I have the ldps on the factory exhaust right now. Only reason, I really want to hear some systems in person before I pull the trigger again. If there’s any FI Black Friday deals, there’s a 99% chance I’ll place an order. I have a meet with some local guys this weekend so I’ll get to check out some other cars.
No particular reason I’m waiting on the catback other than wanting to hear some systems in person. It’s definitely on the list for sure. FI catback and Z1 built LSD on next up for the car. I guess tomorrow’s dyno will determine that order.
 

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Discussion Starter #10
EcuTek tuned at SOHO Motorsports in Charlotte, NC. Graph attached. I’m thoroughly happy. She’s a monster on the streets and boost is definitely coming on much quicker with the LDP’s.
 

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EcuTek tuned at SOHO Motorsports in Charlotte, NC. Graph attached. I’m thoroughly happy. She’s a monster on the streets and boost is definitely coming on much quicker with the LDP’s.
Yes, sorry. On 93
 

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Thanks for sharing Alex. I like the 10 / 15 / 20 PSI comparison.
 

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I have those HKS downpipes on my redsport with FI resonated midpipe exhuast and it is the same noise level as the factory sport exhuast (bordering on too loud for an old man like me) but the power is noticable and addictive. No tune.
 

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Discussion Starter #15
I have those HKS downpipes on my redsport with FI resonated midpipe exhuast and it is the same noise level as the factory sport exhuast (bordering on too loud for an old man like me) but the power is noticable and addictive. No tune.
Which system do you think is quieter? The hemholtz Infiniti axelback is beautiful and I was contemplating running it behind a Tanabe y and resonated midsection. Truth is, I drive tractor trailer 60hrs a week for work, so I couldn’t be happier with how quiet the stock exhaust is on my ride home. If I could find a full 2.5” system that sounded no different at all I’d opt for that in a heartbeat. Being tuned running higher boost and upgraded intakes, I really want to create an equilibrium and cancel out the restrictions on the back end though.
 

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EcuTek tuned at SOHO Motorsports in Charlotte, NC. Graph attached. I’m thoroughly happy. She’s a monster on the streets and boost is definitely coming on much quicker with the LDP’s.
Do you have a before and after dyno of the downpipes? I am curious because I believe there is little gain in HP with just downpipes.
 

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Discussion Starter #17
Do you have a before and after dyno of the downpipes? I am curious because I believe there is little gain in HP with just downpipes.
I don’t. The downpipes were installed at the same time as the tune. The secondary cats are the biggest choke point in the exhaust system. There may not be much to be gained at stock boost levels (not too sure) but I am certain it makes a substantial difference on JB4/ tune.
 

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Which system do you think is quieter? The hemholtz Infiniti axelback is beautiful and I was contemplating running it behind a Tanabe y and resonated midsection. Truth is, I drive tractor trailer 60hrs a week for work, so I couldn’t be happier with how quiet the stock exhaust is on my ride home. If I could find a full 2.5” system that sounded no different at all I’d opt for that in a heartbeat. Being tuned running higher boost and upgraded intakes, I really want to create an equilibrium and cancel out the restrictions on the back end though.
I'm new to this platform and as yet to hear "other" people's exhaust set up but if quiet is what you want I would say it has to be the Invidia Gemini exhaust. I recently just installed the Gemini and it is fairly quiet as some people have complained about it. I personally love it and couldn't be happier that it's not that loud. It sounds like a muted G35 and not much louder at WOT than the "FAKE" piped in noise in Sport mode, it's just now the noise is natural. I'm thinking this will go well when I decide to get a LDP.
 

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The FI CBE w/resonators and touring mufflers is pretty quiet too yet provides the performance. I did turn off ASE in the diagnostic menu though.
 

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+1 to Avedis53's comments.. I was very weary of changing out my exhaust b/c I'm a bit older and didn't want to own a rice rocket. I settled on the FI resonated cat back and it's perfect for my needs. Very minimal interior noise but sound comes on when you step on the accelerator.
 
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