I shaved off 4 seconds at road atlanta (same day and conditions)
going from
275/35/18 front
285/35/18 rear
apex arc-8 18's (6 pounds lighter than stock zcp's)
to
275/30/19 front
295/30/19 rear
stock zcp wheels
both on michelin pilot super sports
I attribute it to a tad more traction in the rear and lower sidewall/less tire squirm
