OEM arrangement on my car is like this.

Front: 7.5" wheels / 225/50/17 tires
Rear: 8.0" wheels / 235/50/17 tires

I have replaced all four tires with 245/45/17.

I know this is not recommended (and possibly a dumb question), but would it be a big deal to switch the 8" wheels to the front and the 7.5" wheels to the back? I'm just trying to avoid paying $80 for removing and re-mounting, and plan to only use this arrangement for about three months - until these tires are autocrossed to death.

Why do this? The front tires are looking rough, and they are "feathering" aka "cupping" - a common problem on the 350Z. Basically, this means uneven treadwear on the inside and outside edges. It probably doesn't help that I keep 32 PSI in them during autocrosses. I can also hear a slight sound on the front right tire. It sorta sounds like it's flat-spotted, but it's not.

I realize that the best idea is to buy new tires now instead of waiting. If that's what I've got to do, then that's cool. I was just hoping to get more than 9 months out of these tires.