I would recommend not disabling this unless you like banging against the rev limiter when in manual shift mode. Because of how slow the manual shifter reacts the ecm/trans just have a hard time keeping up. In Regular drive & Sport mode(non manual) it works great but as soon as you take over shifting if you get even close to where its supposed to shift it likely won't and there is a good chance bad things will happen, I've tested it pretty throughly and while it helps me shift at a higher rpm pretty easily while in sport mode it makes manual mode pointless for the most part.