Judging from these comparison videos, it makes quite a bit of difference, (espeically 'down revs') - seemingly with any exhaust...

http://uk.youtube.com/watch?v=5ZBFaS...eature=related

http://uk.youtube.com/watch?v=VBEe1Z2lvh0

I'm soon to have a J's decat fitted to a Mugen, I hope to get the same 'rasp' letting off the accelerated as can be heard here....??

 

A decat will make louder noise on a performance exhaust becuase of the larger piping etc.

On a stock exhaust its barely noticable, its every so slightly louder the biggest thing is the rasp noise at 3.5k rpm.

 

Mugen and decat is

Mine didn't rasp though.

 

yeah the rasp was obviously from that invidia, - still, it seems that a decat makes more of a difference to the noise than i originally thought

 

Yup, it's good on the Invidia.
After a really good caning its note changes froma rasp to a throaty roar.
I was demonstrating the car to a mate with a 350Z and he volunteered the same opinoin when we stopped.

Lovely tune, even with the bungs in.

 

PJD you are welcome to stop by and listen to mine, I am in SW London have a Mugen Manifold Berk Decat and Mugen Exhaust fitted, I have a crap video taken at the weekend, sounds great though :-)

http://uk.youtube.com/watch?v=sgTmjGsNNyQ