I run mine on s3 basically all of the time now and nothing more than s4. s6 is just far too brutal, even s5 is a bit too much sometimes in my opinion.
You should NEVER lift in an SMG car, once calibrated correctly you shouldn't need to. And if you do, it'll just slip the clutch overtime as it adapts.
According to the US guys who have been dissecting the coding for the SMG tune for both standard m3 and CSL the difference is vast. The S5 shift speed is about the equivalent of the S3 shift speed in the CSL.
The torque ramp up is also 100% (in the CSL) vs 60% (in the standard M3) - this is what gives it that instantaneous perfect rev match in the CSL.
There are apparently 6 different maps for the DME for the upshifts and 6 more for the downshifts characteristics - each of those incorporating a full throttle map (100% torque load)
It is now possible to fully flash the CSL SMG software together with the corrected CSL DME codes to match (you need to do both, otherwise it is pointless as it'll just give you the higher launch modes and slightly better upshift speed, but you lose out on the downshift torque match from the DME).