I think it may have more to do with what tires you have. I too am running 275's all around and have no issues tramlining. My tires are Firestone Firehawk Wide Oval Indy 500s, I picked them up during a sale for pretty cheap and have been surprised by how well they have performed. They have plenty of grip, ride good, and are quieter than the 2 last set of tires I had.

 

If you have a V-6, why wouldn't you just run 275 all around with 9's or 9.5's ??

You'd get the wider hard turning front tires and plenty of rubber in the rear for your HP level. Erik

 

For maximum grip, I believe you would want to run the widest wheels possible. I did look at some 9.5's though. 9.5" Enkei NT-03 was on my short list of wheels to choose, but they lost due to them having that weird 2 valve stems per wheel setup. Since this car will be autocrossed, 2 valve stems means I will have twice the chance of breaking one on a cone.

I wanted to get as close to the factory tire diameter as possible so the speedo wouldn't be off too much. For that I would need a 275/40 in which none of the top tier street tires are available. At least not the ones I looked at. Yoko advan, Dunlop Star Spec, and Hankook Rs-3. 265/40 is the closest, with 285/35 being the next closest. So I went with the 265's.