I love my MAC Off Road H-pipe ($159) and Flowmaster Original 40 series mufflers ($45 on ebay each) then just find a shop. You can't avoid some of the raspy noise especially above 3500RPM, however my set up is a good deep tone until that point. 8-6 = 2 less cylinders, thus the sound is different, but still a huge improvement over stock silence. Tell your friend to youtube some videos V6 mustang
exhuast clips. Best bang for the buck, flowmasters all the way.
2002 True Blue V6 to GT Vert
16.1@86 as an auto 3.8
2.15 60', 9.3@77, 14.4@96 as a 5spd SOHC 4.6