The S65 and S85 are road car engines, not racecar engines. They're also hardly BMW's highest performing motors. Even Dinan built engines don't suffer from that problem.
The S54 is also notorious for VANOS issues and cam drive failures. I had to replace the solenoid pack on mine but elected to not upgrade the drive while I was in there.
4AGE is 4cyl 11:1 compression producing 155hp with 7200rpm redline.
S85 is 10cyl 12:1 compression producing 500hp with 8250rpm redline.