So im swapping my swap from my 99 integra LS into my 97 GSR shell. The LS does not have any exhaust, as for the GSR. I keep reading that the GSR and the LS have different length exhausts? Which do I need in this case? B18B1 into DC2.

 

The only differences between those two exhausts is on an OEM exhaust setup. The GSR, 94-99, had the primary O2 sensor on the CAT itself while all other tegs had them on the A-pipe (which is the pipe between the stock exhaust headers and the cat). So a stock A-pipe for the GSR would be a bit shorter, while the CAT would be a bit longer. And vice-versa, the LS A-pipe would be a bit longer while the CAT is shorter. Everything before and after the A-pipe/CAT combo is the same, dimension wise.