The SZ-R for me has a substantial problem with understeer and so wears the front tires at a very much higher rate than the rears(one of the worst GT5 cars I've driven in this regard). I expected it to handle a bit better having less power but have found the RZ to be actually much better balanced as well as obviously being faster in a straight line.
This is in stock trim, you can probably improve it substantially with some proper tuning.