Hi everyone, this is my first post on NAM, and I was wondering if anyone had any insight in an exhaust "upgrade" I'm pondering.

I just got a 2016 F56 JCW and wanted to do some light upgrades to it, trying not to exceed 250-260 whp. I'm not a big fan of the pro exhaust so I was looking to do something custom with Vibrant resonator/mufflers. With the stock JCW exhaust piping being 2.75 inches (70mm) it makes a custom setup tricky - most universal mufflers and resonators are either 2.5 (63.5mm) or 3 inches (70mm) so keeping the same diameter pipe of 2.75" is not likely.

I've read that increasing the diameter of the exhaust without adding much power will kill low-end power and gas mileage at the expense of more top end. But my JCW is my daily driver and I just want a bit more sound and better looking tips, nothing crazy.

Would it be a bad idea to replace the stock 2.75" exhaust (2nd catalytic converter, resonator, muffler) with a less restrictive 2.5" exhaust from the downpipe back with a smaller resonator and straight-through muffler to 3.5" tips?

What do you all think? Thanks!

 

The old hot rodder rule of thumb says "for every 100hp you need 1-in of exhaust diameter". In reality, it's a little bit more complicated than that. But, following that rule of thumb, the OEM exhaust is good for ~275-ish hp, which is within your goal.

Turbo engines, in general, like low restriction exhaust because it helps the turbo spool up better.

If you just want better sound and maybe different tips, I would just pick up one of the off-the-shelf muffler replacements, and call it a day. I like the sound of the Magnaflow box....

 

Find someone selling a used GP3 exhaust.
I did!!!
Sounds awesome.
2.75" pipes, yes it has a cat and resonator, but the muffler is pretty much straight through acting as
a resonator, rather than a muffler.
It has dual tips, but the left tip you can see through the muffler to the mid pipe.

 

gotta 3" Magnaflow S.S. exhaust w/4" tip also got turbo pumped to 25lb & 300fwhp. if you go big make sure your tunes are up to it. you'll know it's there. got S.S. because I got water/meth. inj.