i run 15mm in the front and 25mm in the back, on a sportcross, all bolt on. the fronts are hubcentric made buy h+r, i love them. the rears are non hubcentric, cheap ebay brand, they vibrate and i had to replace all the lugs in order to torque my lugs. the bolt on ones are easier to take on and off, so if you are trying to perfect a stance, or for a temporary setup (like mine) they are better. they are heavier than the slip on kind cause they have two sets of lugs. slip ons take more work, if you have to put in extended studs, but for a permanent setup, they would be better.