Obviously more RPM's quals more available HP. Assuming the tuner keeps the torque curve aligned.

Higher shift points lets one goe farther accelerating in thelower gears, puttingmore of the HP to the wheels.

Our engines are limited by engineering to conserve them and extend life span. They are overbuilt and can standd being driven closer to their design limits. It is up to the driver to control his urges and keep things within range. But the limiter can be raised safely to say 6300 RPMs without issues.

Have a tuner like Eurocharged do it for best, safest results. They can make the limiter different for different gears and change shift points to match and optinmize performance.

I have a manual tranny and even there, they set the rev limiter different depending on the gear I am in.