Here's some track video on the PSS and stock wheels (with pressures as delivered and driven to the track). I was taking it a bit easier on this shorter layout so the understeer, while there, isn't as visible. I ran the longer track (still short) this weekend and pushed harder and the understeer was egregious. I'm pretty sure under the current rules (essentially SCCA autocross classing rules) the M2C isn't going to be competitive in time trials with a well-driven C6 Z06 but it's still fun.
Better pads and higher temp fluid will help as well, but nothing (legal for class) is going to close that 100HP gap.