I have a full set of Firestone tires in my garage, about a year old I bought for my Tbird and never put them on. They are Firehawk P235/50 R17 95V. Would these be OK for the Mustang GT. I measured them and they seem to be an inch wider than factory. I know I would loose the Z rating but that's for speeds over 120 I believe. I don't drive that fast anyways. What are your thoughts??