I have the stock Goodyear 245/45/17's, almost due for replacement. Heading up to Barber Mortorsports Park in Sept. with the MCA 30th birthday celebration to put my car on the track. Any recommendations on a good replacement tire for the road course which I could run out on the street till the tread is done? Will a 255/40 fit on my 8" wheel? What benefit would 18's give me on a road course?