What about magnaflows?
I went from old flowmaster 2 1/4 catback to the 2 1/2 catback and it's much louder with the same brand, which is 40 series 2 chamber flowmasters. I like it also, since it matches my 2 1/2 inch off road x pipe. X pipe is louder and better for engines producing serious power.
Look at the two above. Imagine when you are up in the mid to high rpm range and the exhaust flow is increasing in speed. Will it miss the sharp turn of the H pipe at high speeds while the x pipe forces the two exhaust flow paths to meet?
Think about it.
pypes dollar for dollar is the loudest for muffler. next would be bullets or some other glasspacks tyled muffler....but pypes is just really str8 through muffler with zero deading design, i do no tlike mine im going for 40's or something to quite her down...
Magnaflows sound great, but are on the quiet side. If you want LOUD go with spintech prostreets. Cam/Intake/Clyinder head have as much to do with how loud the car is as the muffler.
I have noticed that alot of people are against the dumps, which is understandable there is nothing like having shining tail pipes coming out of the back. I am going to look into MAC flowpaths or the spintech exhaust. I will tell you guys one thing though, I have had my flowmasters on my car for years and I think it sounds too hollow. I dont know if anyone else thinks this or if it is just me. Any input on this would be great though. There is nothing like pulling up to a foxbody stang with a nice rumble to it. Put fear into chevy owners!
My AFR headed 347 with prostreets is louder than my '89 GT open headers.....