I have a set of 18X10 Apex wheels with 275/35 tires mounted. Since my track time is minimal these days, I bought street tires for them, Michelin PSS. I have only had one track weekend with them, and maybe 1K street miles. The advantages on track are what you would expect, and I was pleased with the setup. For street use, I’ll mention a few minor issues which may be of interest, or not. Tramlining and noise from the front is elevated a bit. Steering feel is probably slightly affected, but I expect your choice of tires might have at least as much effect there. With wheels of 25 offset, the fronts are out just a little too much for my taste, but I’m not sure the offset could be much more without inner clearance issues. And this is a subjective thing. I think the OE fitment is fine, whereas many seem to prefer sticking them out until the wheel bearings scream foul. Overall, I believe the 275 square setup is good, and the handling and rotation advantages outweigh the minor annoyances. I find the E92 M3 to be noticeably more neutral in handling than the E46, both stock, but I still appreciate the influence of the square setup.
2011 Space Gray Coupe, DCT, ZCP, StopTech ST-60/ST-40 BBK.