I'm looking to get a Flowmaster muffler (40 or 50) soon, and I went to the shop where I get all my work done and he brought up some points that I'd like to get your opinion on... He said that with Flowmaster mufflers in general on the 4.0 V6, it would sound terrible, and that there would be a huge performance loss? I've read on here that it does loose a bit of performance, but the way he was talking it would be very dramatic and very noticeable. He also said that I would not like it one bit. BTW, I've searched but didn't find much pertaining to this in particular... This guy builds vehicles to race at the local drag/race strip, but is he feeding me a bunch of BS on this? Thanks in advance!