Perhaps you should check your pressure gauge is accurate Mikew or try another and compare

Wish i could get it to ride a bit smoother because i really like my 2!
What size tyres do you have on your M2?...16"?, 17"?...If so, then the answer is very simple...Your tyres are unecessarily low in profile than they need to be...Buy smaller wheels with deeper tyres and your ride problems will be over.

I had the same problem with my 2003 model TS2 D which was fitted with 195/50R15 tyres on 6"x15" 5 spoke Mazda alloys...I replaced them with the only other tyre option for the car stated in the manual, 175/65R14 tyres, and I fitted them to 5.5"x14" five spoke Ford Alloys and the ride was greatly improved. These new tyres also gave me three other big benefits, lower road noise, lower fuel consumption and replacement tyres are considerably cheaper too.