I think the current sound system, with just slight modifications, would probably work a lot better if there was a "map" of the settings at various engine speeds and loads for the program to interpolate between. At the simplest you could have just have two points for no throttle at idle and full throttle at the redline to replicate the current system (after removing the idle volume boost and off power settings.) If you wanted to give an engine a "VTEC" sound one could add some extra points at high throttle/RPM combinations to make the engine tone change appropriately.

It would seem to be easy to implement, with the GUI elements being even simpler, probably just RPM and load sliders and add/remove and next/previous buttons and a numeric display of the current data point.

Oh yeah that would be FantaStic!

I like that idea.

I'd also like a simple way where are just sound clips for specific RPM's. Yeah, not very accurate but it does give a very good sound.

Well, LFS Carsound RemiXer used this, but it just sounded off.