I just put on a HTT62/71/13SS and Mach 4's. It's alittle laggy on the bottom end. Gotta learn to drive it down low in the RPM'S to keep it from smoking alot, eazy on it, but once it gets to about 8-10 psi its rocket time:ft:. I like the combo, egt's are alittle warmer than the stocker and mach 2's. Once it spools up it cools thing off. what trans are u running? might want to start planing on upgrading that also.