I have heard the Borla system before....wasn't bad, but it wasn't good either.
The spintech system sounds AWESOME. The clip I have of it is with long tubes and an off road hPIPE. I'll post links later when I get home, I put them on YouTube. Same username as the one here (nmcgrawj).
I've heard clips of the dynomax, not in person tho. I Definitely give the nod to spintech.