I have a Magnaflow on my 1998 Chevy 454 Dually pick-up, and it is EXTREMELY deep sounding. Sometimes at low trottle you can't hear the rumble but you FEEL it. The nice thing is that it's not loud and obtrusive. Just perfect. Anyways...I also have a 92 400E and considering doing the muffler work on it as well. I just never thought about Magnaflow for it but now I might consider it. I would have to go with the oval dual tips though, and surely not upturned.