I put a GMPP exhaust for the W body cars on my 2001 SE with the 3.1 single exhaust and was shocked at the increase in performance with the U bend delete after the cat as well with a 2.5 inch straight pipe with the O2 bung. The GMPP exhaust is actually a magnaflow all stainless 2.5 inch duals with polished stainless magnaflow mufflers and resonator. $450 from gmpartsdirect.com. This exhaust advertised as a magnaflow at other retailers is $800. Sounds real good and BIG increase in performance-equivalent to a stock 3.8- I should know since I have had a 98 GT, 2004 Impala with the 3.8 and a 2001 Bucik with the 3.8l. U bend delete and GMPP exhaust-3.8 power with 30 MPG.
