magnaflows sound best with an x-pipe because they have a straight thru design. plus you get a hint more power. h-pipes sound better with chambered mufflers like flowmaster. straight pipes get raspy sooner at high rpms. but im biased, considering i have the same thing
I had straights with flowmaster 40 delta's on my 96 V6 Coupe and I was shocked by the sound as it sounded better than I expected. However, the trade off was CEL issues that were off and on coming from the sensors near the cats. Although...the CEL issues might have been a issue before I added the exhaust.
When I got the 04 V6 Vert, I went with a x-pipe and Flowmaster 40's. I noticed a performance gain, but a less aggressive tone. Its fine by me as I don't want any CEL issues again.