does anybody know what the stock pipe diameter is on an 06lt 3.9?

 

I want to say 2.25"

 

thanks.
well maybe that magna flow system with the 2.5in tubing might actually be slighty worth it.

 

Don't buy a catback for power gains- buy the one that gives you the sound you like. Modern stock catbacks on these cars aren't terribly restrictive- so choosing one over another, or one over stock because you might gain an extra 1 or 2 hp isn't worth it if you aren't happy with how it sounds.