Help me with some tires

[Z-owned]

Ok i just bought some 06 350z wheels they are 18x8 front and 18x.8.5 rear Currently the fronts are wrapped in 245/40 yokohama's with alot of tread still well the rears are wrapped in 245/45 potenza's and need replacing. My question first off is how bad is running two different brand/style tires? I would like to get some wider rears and i believe 265/40's would be a little to much in the rear for the wheel and 255/40's aren't very common. Looking for input on what to do.

[musashin]

Running two different kinds of tires is generally considered an extremely bad idea when doing anything above normal sedate driving. 245 is about as wide as I would go on an 8.5" wheel. It's too much for an 8" wheel though. Maybe put the good 245's on the rears and buy some 225 or 235's for the front?