I own a UK DC2, and a lot of good stuff written in this thread.
Back to tyres: I ran on the RE010 for 7k miles (195/55/15), then I changed to the RS2 in 205/50/15. The RS2 is a better tyre then the RE010, more grip in all conditions, and it's more stable at high speed, I would never go back to RE010, really! RS2 feels more 'proper', where as the RE010 feels nothing special by todays standards.
Once you fit RS2 however, due to grip it exposes flex/roll. The car looses some of it's dynamics as extra grip it rolls more. To counter this I fitted the OEM tower brace, and a H-brace (4 point front lower), and these tightened the car, and returned the dynamics back to standard. When things do slide car is going faster on RS2 then it was on RE010, however the way it behaves is like the stock car (no extra braces) on RE010 - hope that makes sence..
Had lots of tyres 2 generations of F1 / Potenza S03 / various Michelins and Pirelli, RS2 is best so far.