i have a 4.5 base andi have to change out my rear tires becasue there showing wear and i was going with these highperofrmance W rated kuhmos that they use on porshes but was wondering if i should go a little more bigger on the back, can some one give me a optimuim size and width to go with for the back. also im using stock 17s so bare that im mind

 

245/45/17front and 255/45/17 rears they are made in the Kumho MX's

 

are the mxs th best tire theymake

 

i have Kumho MX (see sig). nice tire for the price. good ride and little noise