Went down to City Suspension today and got the shocks he recommended I put in.
Bilstein B8's. This matches the general opinion on this forum as a good cheap option to upgrade the 6MPS dampers.
I have only driven it home over about 15mins so the impressions a a little early to give a final opinion, but interesting anyway.
I find the overall ride brilliant. The perfect blend of luxury and performance. I can notice bumps in the road but they no longer are felt through the steering wheel (previously with stock dampers and super low king springs). I tried a hairpin corner (my favorite on the way home) at medium speed, not full attack as I was in peak hr traffic, and the car held level all the way through the corner. Absolutely brilliant.
My car suspension matches what the car designer wanted. The 6 MPS is designed as a sports/luxury car, and it now feels like it. It previously didn't.