nismofly wrote:you wont put the power down any better with a 9.5 rear than you would with your current size, straight line traction is all in the tire compound
it sounds like youre looking at custom wheels with those sizes, max for 16s is 16x8 front, 16x9 rear, with a 225 / 245, and i dont even know how many wider tires youll find in those sizes
if you want wider than a 225 for looks purposes, id go with a larger wheel, 17s or a 17/18 like youve got...i dont know what the other specs besides the size on c5 wheels are but those sizes can work if the wheels would fit
Extra width is only going to give you more lateral grip. Traction (grip) is completely dependent on other factors like tire compounds, suspension, whether you have an LSD or not, etc.
Take a minute to browse some of the suspension and tire faq's that are stickied in this forum. They are more in-depth.