i do not own a maserati yet but from my experience on many cars and working in the tyre business long ago. going up one size wider i have never seen a problem. on my vette the stock rear tyres are 275 i have the car lowered 1" and have 10.5" wide rear wheels and i am running 315's on the back with no problems. if it is such a good deal go ahead and try it if they don't fit you can sell em and get the right size. the wheels will allow a larger tyre on no problem.