Exhaust for 2000 GT, SLP or Flows

[Hammer]

While I can appreciate that, I have had flows with a stock h-pipe and headers., and while it is better than stock sound, it is not that loud and it certainly isnt great. There are many more mufflers that have a much greater performance gain as well as a boost in sound. Anything straight through will not only have a better sound, but it will not be chambered like the flows. If you have ever seen a disected flowmaster, they are very restricted in flow. If you like the sound of flows, go for them. I have 2 chambers on my 90 and my 01 and I am sooooooo ready for a new sound. Every other mustang on the road has flows, except for the smart few.

I personally have never used flowmaster mufflers, but I know many that have some flow 2 chambers, and they are quite loud.
Some of this can of course be attributed to other after market exhaust pieces (some had high-flow H pipes), but they were certainly much louder than stock.
(I guess it all depends on how you define loud...)

When I had the 98, I actually used a MAC setup.

They sounded quite aggressive without being as annoying as some other setups... much less of a "drone" at cruise speed also.

I also like the sound of a DynoMax setup...

As far as horsepower...
Anyone expecting to see much of a difference (if at all) on a dyno by just replacing mufflers is in for a rude awakening....