i actually just put new tires on my coupe and i went with PS2 (MO) this tires are great, the level of grip that you get is incredible.
the "MO" is a special compound maid by Michelin for Mercedes Benz, this tires are used for the SLR and they are maid to grip (softer compound) and handle larger weight (harder side walls). (you will see the letters on the side of the tire)
i actually went up in size, 245/40/18 in the front, and 275/35/18 in the rear.
the car balance is great, i have no understeering what so ever and i also see that in fast acceleration the tires tend to hookup better that with the stock PS1.
in my experience, more rubber in the back makes the car jumps out from a fast slam on the gas, instead of spinning the wheel. i also feel that in power slides, the car is neutral and even reacts very predictable.
i have seen no rubbing on the tires and i actually went on the norcal event with really windy roads and i felt no rubbing, just a good overall initial turn-in response.
i recommend you fill them up with nitrogen, the car feels a little different, but the temperatures are really controlled.
-willie