Need your help with wheels/tires 1997 S500 coupe
 

Well, now that I've got my cam oil tubes all taken care of (went with aluminum after blowing out new plastic ones)...I've decided to keep the car for quite some time to come. Currently running the stock 16" tires and wheels....contemplating going with 18's when the tires are spent...(probably 6-9 months), but I like to plan ahead. My mechanic is suggesting 285/40-18's rear and 245/45-18's front, staggered. Does anybody know:

A. How this car will handle with the 18's vs. 16's...everything I've read seems to be positive so far.....and

B. Will the car handle 285's in the rear on 9.5" wheels, or is there a different combination I should be looking at?

I'm not trying to overthink this, I just dont' want to have to redo it due to poor ride, or wrong sizing.....

It's currenlty running 235/60-16's

Thanks in advance for any input....btw, the car is black, including the body molding.