I suggest a 17" size since they're available in 275/40-17 which is what I recommend for the rears and either a 245/45-17 or 255/40-17 for the fronts. Running a narrow front tire size seems to make for a sharper turnin into the corners according to another Z guy who I spoke to who ran the staggered sizes (I was using 245/45-16's all around at the time). I'm going to be trying out the A032Rs since they seem to have good wet weather traction as these will be my only set of tires. My car is now pretty much a track car with occasional weekend drives so tire life isnt so important to me. Oh, and good job on the way bars. You'll love them!
John Yim (Houston) 91 ZTT Stage...stages are confusing. Just read the mods. :) SM2, Houston Region SCCA "...Just as they're about to catch me... Twin... Turbos... Kick... In..."