The Dinan Performance DCT software enhances the driving experience of M3s with DCT transmissions with quicker & smoother upshifts/downshifts. It greatly improves the overall smoothness in D mode when driving normally, yet tightens up the shifting feel in S mode with quicker engagement. This is a must-have upgrade for any M3 DCT owner. "It makes shifts faster but does not change shift RPM. Shifting is actually smoother than stock." - Steve Dinan