I guess I don't drive my One hard enough or something but I've had two sets of mismatched tires and barely noticed it. Plus with this set my fronts were new when I already had 25k miles on my rears. Also the Toyo and Nitto models I was using were fairly similar. When I bought my wheels they had used Falken fronts and Hankook rears.
To me, the One just pushes and rolls going into a turn then spins the inside tire coming out. Mismatched tires don't really hurt or help that much. But I'm biased, my main other car is a Porsche 968 which to some people is one of the best handling cars ever.
The LSD doesn't nearly help enough to make summer tires work when they are worn out and when the weather is cold. However when I installed it about the same time I got new tires it was amazing how much difference there was. I had gotten used to what it took to break traction on my prior setup and then with the upgrade I think I went like a month before I ever got my first traction control light! For sure now when I spin I don't instantly get traction control interference, and barely at all if I hit the DTC button once and I'm not cornering.
I think some of the guys on the other thread are gonna try big PSS widths on their fronts very soon. Just give it a few more weeks and you might have a better idea there too..lol.
Injen, RR OCC, MadDad Whisper, donut spare, 19x8.5et43fr 19x9.5et45r Volk LE37's, rear fenders rolled/pulled, Nitto 555 225/35fr PSS 255/30r, KW V1's, AR coated catless dps, Cross strutbar, CF grills and license plate holder, rearseat removal, iCarbon diffuser and front lip, ETS black anodized FMIC, M3 control arms, Quaife, ER chargepipe, ForgeDV's, Topspeed Custom Tune, V3sims, Braille, Andrey_GTA rear hub mod.