I have flowmasters, other than sounding somewhat like a mustang exhaust, I love them. The only other ones I would buy would be the Dynomax's. In perf. tests, the numbers were almost identical.

And rainbow does excellent work and are very muscle car friendly. The guy wouldnt even pull my car into the bay after I lined it up with his stall outside. And they did no welding until they made sure it was ok with me first. good people.