UPS is dropping off a Victor 5.0 for me today. But if my heads werent ported I'd go with a RPM II. In Jan 2006 issue of 5.0 they tested the SSI, RPM II, SysteMax II, Track Heat, and GT-40 on a 347. The SSI was almost identical to the GT-40 on the dyno, and the other 3 posted within 5 HP of each other with the RPM II just barely squeezing out 450 for the highest HP. But the TFS is a lot less $$$ than the others... made in China perhaps?