Go staggered for cosmetic reasons.
Exactly. I've been saying this for years. I haven't done the math for M3P, but for a Model S with 265/245 staggered wheels/tires, the rear staggered tires only add 4% more contact patch area. Marginal, at best.
Unless you're on a track, with a car built for track purposes (say,
@sorka's P85D+ with monster sway bars
), and pushing the car to the absolute limits of adhesion (in the turns), staggered width setups* provide essentially no performance or handling differences in normal street or highway driving.
The drawbacks (can't rotate the tires, limited selection of staggered sizes in performance tires) far outweigh any benefits (none, really). They're really for bragging rights more than anything else.
I'd also argue (my opinion here) that even cosmetically they don't make any visual differences. On the Model S, the difference is .75" in width of the rear tires. That's the width of your thumb. Are you really going to tell a difference far enough away from the car to see that? Yes, the tire profile is also a tiny bit smaller on the 265s from the 245s (about 8%) , but is that even noticeable?
*Some performance cars have staggered diameter and width wheels/tires (usually smaller front wheels). That kind of staggered setup can have a non-marginal impact on street handling/performance.
