I wonder why they removed the KIPS. It mentions that in the Special Setup section of the specs. That thing was probably insanely fast.
On certain engines KIPS systems only enhanced midrange torque and throttle response, but adversley in some situations hurt top end. Perfect example was the '87 KX125, first year of KIPS, and that engine was a friggin' terd....
On my CR125 powered shifter kart, performance engine builders actually "plug" the power valves to enhance more top end hp up above 12,000+ rpm's