Houston -
I'm running a G-Force with a few options: I have the boost limiter removed (basically reproduces the functionality of a BCC), the top limiter is removed, and the most important thing for me, the top rev limiter has been moved up to 7800RPM.
Honestly, it's pretty poor bang-for-the-buck, but didn't know of alternative at the time I needed it - I bet the Toyomoto upgrade is cheaper. I did not choose to change the timing/fuel maps - though now my ECU has a socketed PROM so I can easily upgrade to a different program.
The *only* reason I upgraded the rev limit was to provide more headroom in my (optimal) powerband which is now pushed to about 5K - I don't know how advantageous it would really be on a stock twin car. FWIW, I drive mine way into the 7800RPM range pretty hard and my valvetrain has been fine so far (though the car is only driven ~1 day a week...)
FYI, you an get a complete valvetrain upgrade using Ferrea components (spring, retainers, etc.) for about $1200-1300 that would handle a 8K redline with much more tolerance that the OEM parts.
Seeya -