Resonated. Think of it like the rest of your exhaust. The size of the resonator (or muffler) will determine the sound.

Small resonator = more noise
Big resonator = less noise

The piping diameter makes a difference as well. The bigger the pipe, the more noise it will produce & vice versa.

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Thanks alxtheoreo. So a small resonator will increase the noise. What will reduce drone and rasp or is it impossible to increase volume without drone and rasp. Would I still be looking at a catted front pipe or going with a catless? Thanks again guys. Complete noob at this.

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Personally, I would look for a catless & resonated front pipe if I want to swap it out. There's very few on the market. HKS has a double resonated front pipe that's 60mm in diameter. Invidia has a single reaonated front pipe that's 63.5 (or 65) mm in diameter.

Don't believe the words that a high flow cat will eliminate drone & rasp. It'll just produce the same sounds as a straight pipe but at different engine loads.

The other option is to keep the stock piece. It's very good at keeping bad noises at bay.

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Catted or Double resonated are pretty good imo.

Could I just go with the perrin unresonated cbe for more noise and then use a catted or resonated front pipe to remove the rasp and drone? Do I have the right idea?

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Cats and mufflers help with volume most, but help with rasp some.
Resonators help with rasp most, but help with volume some.

You'd do okay, I recommend doing one part at a time, and using the next part to adjust further.

IMO a resonated Perrin CBE, and high flow catted front pipe sounds great. If you go with a catless header it's going to get louder too, which is when you may want to add another resonator to the midpipe to help where it can.

One piece at at time if you actually care about getting the right volume and sound quality is my recommendation.

I have a catless EL header and MXP SP catback, and don't intend to add any more exhaust components, as I'd like to keep it quiet. If I choose to swap out the front pipe, it'll be a high flow catted, resonated FP like the JDL ultra quiet.

Thanks for your advice. I watched a few videos online. Sounds to me that the 3" resonated is a lot louder than the 2.5 I think I might go this route. May add a catted front pipe to help regulate any rasp or drone. What do you think? I don't want to change my headers for emission purposes.

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I know emissions is different state to state. Most of the tunes with headers takes care of the codes. If they have to appear stock, you can knock the cat out of your stock header, run an OFT stage 2 EL tune, and get 95% of the performance of an aftermarket header, without the cost, or appearance of an aftermarket header.

I think you should get the Perrin 2.5" resonated exhaust. If you want a little more rasp, get a resonated FP OR get ballsy with a header. Changing the front pipe is technically emissions as well, no different from the header as it has a cat in it.

like the other guy said khs and jdl do quiet front pipe but they are expensive. and they may not be much louder than stock one.

its all a bit suck it and see with exhausts as their are son amny combinations

Added info now that opensource tuning and OFT now have flex fuel and map switching capability on some roms.

Any new info to add for this thread for the 2017+?

have not seen a 2017 here yet.


they already have better air filter


The ecu has different programming and appears to run full time closed loop fuel control and does not run rich at high rpm load (from what I've seen on usa model ecu logs)


Header is changed and intake manifold changed.


Due to stock header being better and fuelling control being better you may not see as much gains from header and tunes as you did on earlier models.


but its early days.

Thanks for your hard work steve. I recently switched to e85 and relied on your info. Very happy.

Hello I couldn't find anything on this, so please​ excuse me if it's a double. I have 13 FR-S with and agency power catback. I love the way it sounds and is great quality no issues what so ever. Just wondering has anyone with this set deleted there CATS, of so what's the sound like? I'm concidering it until I have the money to buy a new header and down pipe. Any vids would be fantastic. Thanks the car is stock ATM other than the catback.