I have Carrera III wheels on my 2001 Boxster, no spacer up front and 15mm on the rear. The rear fitment is spot on where I want it, the front could use a 4-8mm spacer but I don't rub at all front or rear so I'm happy for now.
Anyways, onto my question. I currently run the Bridgestone RE980AS front and rear. 225/40/18 up front, 265/40/18 rear. I don't drive the car much in the rain and never in the snow, but I do drive on sunny days in the cold, down to 35-40F. My rears are due for replacement, and I found a great deal on 275/35/18 replacements (same tire, RE980AS).
For comparison, the 275/35/18's are $320 brand new (2020 production) shipped. The same tire in 265/40/18 is $445 new, or $475 for the new RE980AS+. Looks like the + improvements are focused on snow driving, which the car will never do. I've got a Vic with snow tires for that.
From my measurements the 275 should fit in the rear without rubbing.
My question is, would the 225 front paired with the 275 rear cause too much understeer? I just use the car for spirited driving and the occasional commute to work (less than 3 miles). But my driving skills are pretty basic, so I am not pushing the limits of the car at all.
I'm planning on swapping to 235/40/18 fronts when the time comes to replace those, but the fronts have been wearing slowly so I have a year or two I would guess. Might replace them sooner if I find $400 burning a hole in my pocket lol.
pic for reference (also I just cleaned up the headlights last weekend after this picture, so excuse the yellowing)
