Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!
Think my old mk2 ph1 R reg had 13" steelies as standard, 165/70/R13 tyres.
Going from 165/65/14 to 175/65/13 will be a -2.18% difference in circumference. Not major, but means you speedo will be a little less accurate than already. This calculator will help http://www.alloywheels.com/tyrecalc.asp
I'd be more concerned about the tyres. Ideally, you want the same tyres with the same amount of tread on either side of an axle.