satisfied for my purposes: drag racing and a daily driver. They are slightly more laggy than stock (a couple of hundred RPM) and are capable of making about 60-70 more RWHP. Mine made 469 peak HP and 490ish ft/lbs of torque, and the car ran 11.47 at 122MPH in the 1/4 mile. This was with a completely stock Nissan short block (no exhaust manifold or head work), and the usual supporting mods (555cc injecters, upgraded Stillen side mount intercoolers, a JWT ECU, and a good tune fuel tune). I didn't look what state you are in (ie. what octane you have at the pump), but I was able to make about 14 psi on shitty Ca. octane safely. That figure goes up about 1 psi per octane point. Hope that helps, Mark