new cats or y-pipe?
I have the MagnaFlow catback too but I have pacesetter headers no cats and a comp cam and it sounds awesome. If you dont have a prob with taking the cats off then do so and the MagnaFlow will sound so good it isnt even funny.
Good Luck!
Its easy to remove them, but you'll have to pay for an ORY that mates with the stock manifolds. Or you could just have an exhaust shop make you one.
I say just leave the cats alone. 5HP isn't worth the trouble.

