I was too busy to post these while I was at SEMA and just got around to doing it today. For as much hate as there has been against the MKV Supra, it was amazing to see so many of them at the show. It was by far and away the most popular car. I'm guessing next year it will be the Corvette. Chevy...
No, in the GT-R, there is already a 30mm difference in width front to rear, so I kept it that way with the aftermarket tires I bought. The suggestions I had made for the OP were less about width and more about keeping the rolling diameters the same. If the difference in diameters is too great...
You really want to get a fully forged wheel, not flow formed or hybrid forged. The best bang for the buck on a fully forged wheel are the Titan 7. I went with a custom set of Rays Volk G25 wheels on my GT-R, and was going to get some Titan 7 wheels for my M3 until some kid crashed into it.