I'm looking at getting 17's for my 79 Z next year. I currently have 235/60R15 ft and 255/60R15 rr. I have dropped the front and rear about 2 inches and I like the stance. Fender to ground is 25 1/4 inch in ft and 26 inch in rear. I have been looking at 17X8 wheels with 4.5 back spacing. The tire sizes I've been looking at are 245/45R17 in ft and 245/50R17 in rear. I do plan on doing some autocross, but a lot of cruising. What do you think of my thoughts on sizes? Thanks in advance.