It is cool
I don't want holes in my fenders and want this to be reversible, so win-win.
There is one downside to all of this - pulling out the fender raises the wheel arch slightly, about 3/8". So, I ended up with a larger than pleasing wheel gap in the rear.
I had to reduce my rake from about 3/8" to about 1/16" (barely none) just to get it to look Ok again. This means the rear suspension is further compressed which brings about potential issues with the CV shaft not being parallel to the ground, any additional angles created which could impact traction, what will happen when I sit in the car or under full throttle and sqaut, etc etc
Luckily I didn't have to touch the front end to fit 275s. Again, no spacers, just switched from 6" spring on KW clubsport to 5.5" spring and I have 1/16"+ clearance from these fat tires to the perch. 275RRs are wide. I tried on 275 Direzza and I had almost 1/4" gap to perch!
This experiment is probably going to make things worse on the track, but it's just an experiment. I've been super consistent at NJMP TBolt on same tires running 1:28s~1:29s on a clear track, I will be curious to see if the lap time improves. My goal here is to get on the throttle much earlier and see if it sticks.