I would imagine if you modify your driving habits then your vehicle would no longer overheat. If you have to drive at 5k RPM for 15-20 minutes then just don't drive like that and it wouldn't give you issues. I don't ever need to drive my VX like that, even when I'm goofing off in the dirt.
I'm sure the factory system should be strong enough to cool the engine under hard driving, but extreme driving for 20 minutes would put almost any factory stock cooling system to the test, and repeating that would eventually cause parts to fail.
i did that just to see if i still over heated. if I drive on long distance on an expressway at posted speed I will still overheat. it just happens faster if I drive a little harder. the drive was mostaly at 3000 rpm but passing vehicles was at the 5roll mark