I just watched this video from youtube: http://youtube.com/watch?v=ZAX8N6Sjft8

Says:
STAGE 3:
Stock Resonator Removed
Stock PreMuffler Removed
Install Shorter Base Resonat

I asked guys at Golden Muffler (San Francisco) and they said it won't do much. He's charging 45 dollars if there is one stock resonator. I'm wondering about your opinions on this matter. Thanks

 

Well on my S I removed the pre-muffler, and replaced stock resonator with dynomax resonator. I dont think it makes much difference for N/A TL but I do think it would make a good HP difference for a supercharged TL. The biggest reason I did it is for the sheer glorious sound of it. Sounds so damn awesome. There are a ton of threads on this so search around a bit and read on some more feedback before you make your decision.