I have a 2011 GSR and want to stay with as little noise as possible. I read the stock catback is not very restrictive on these cars. I was thinking of changing the O2 housing , downpipe and getting a HFC while keeping the stock catback. I would like some opinions on this setup.

Thanks.

 

Yea people have done that before. It is a restrictive, but you can make ok power with it.. If being quiet is more important than straight performance, than you should be happy with it..

 

It's been done, and people have made good power with it, go for it

 

I was thinking of posting a similar thread What is your opinion of just swapping out the cat with a HFC or test pipe? How much HP are we leaving on the table by keeping the stock catback?

 

I have a 2011 and i have been wanting to do this since i got the car, thank you all for the answer

I currently have ETS intake and uicp and want to get the down pipe and high flow cat from them as well, but do i need the o2 ? not changing turbo but should i replace that at same time anyway and would that help more ? now i need help to little confused.