[84LX89GT]

I've heard great things about the BBK shorty equal length headers and H-pipe (with or without catalytic converters), so that's what i'd recommend. A friend of mine has BBK equal lengths, offroad-H pipe and flowmasters (2 chamber) and it sounds great, although kind of loud. Dynomax Super Turbos would be quite a bit quiter than the 2 chamber flows. I've never heard 3 chamber flowmasters on a mustang, but apparently they're quiter with the same type flowmaster sound. I have the Flowtech Stinger cat-back, and the exhaust has a great tone, but is VERY quiet. Even without catalytic converters there is no drone on the freeway and it doesn't attract attention from it's noise (unless i'm on the gas ). I don't like the stinger cat-back because of the cheap muffler paint which chips off immediately and the muffler rusts quickly unless you repaint it.

I wouldn't get long tubes because they're a pain to install, the headers and H-pipe all cost more money, and also i've heard of alot of problems with the oxygen sensors not reading correctly because of the position they're mounted in the exhaust (how far downstream they are). Just some things to think about, Good luck.