I've looked up and down (including these forums) trying to find out if I can get a 99 GSR 4dr catback to mount on my 99 LS 4dr. I know the 99 GSR header and cat are different lengths, but since both are sedans, the catbacks should line up, right? Or would I have to get a 99 GSR header and cat too? Please help!!

Thanks!

 

you already answered your own question, you would need a gsr header and gsr car to use a gsr exhaust on an LS, or just have an exhaust shop make it fit. Thats what i would do

 

Hmm, I would have figured that the GSR 4dr exhaust would bolt up directly to the stock LS header and cat. Oh well, sounds like too much $ and trouble for me anyhow, thanks though.