RC,
How does that impeller affect the low-end performance?

An aftermarket impeller by itself helps some. But, you shouldn't run the 14/21 by itself as it's pitch is a bit tall. The 14/21 combined with the rest of the kit provides the most noticeable difference.

I ment How is low end performance with the RPM kit ?

I thought I answered that. Sorry. The low end is good. Noticeable improvement over stock.

I think this RPM kit is a very nice package. It offers significant improvement in handling, acceleration, top speed, and wave jumping. A few more mods to this RPM kit and 68 should be doable. I'm at 66.6 and still need to do the exhaust and a taller impeller. I have a 13/19 pitched to 13.5/20. I need a 14/21 at minimum now. For what it's worth, I beat stock 15f's like a stock 15f beats a 12f.

thanks AaronC your letter hepled me to make up my mind about the RPM Kit. i've been thinking about it for a while but now that somebody has it and gave feedback that really helps!

06 15f