Well first you loosen your lug nuts... then you jack up your car....<p><IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/biggrin.gif" BORDER="0"><p>In all honesty, you will be fine, and don't need hubcentric rings as long as you torque the lugs evenly; read: a bit on one lug, go to the one across and tighten that one a bit, then continue in a star pattern until the wheels are torqued to spec, while the car is in the air with the wheel off the ground. This is the proper way to tighten an aluminum wheel. Failure to do this will result in poor fitment, and may give you noise and vibration issues.<p>If you are putting on an 18" Pegasus, you'll want a tire size of 225/40/18 to avoid rubbing. I think a few people move up to a 235, but I'm running the former and am slammed with no issues.
So the wheels fit fine without any modifications e.g spacers etc?<p>I have no idea how to do it myself, but I would ask a local tire place to do it and put the tires on. I just want to make sure they don't rooster it up.
Make sure you go to a good tire place, and you watch them put them on. Make sure they use a torque wrench and only torque to (my mind is fuzzy on the exact number here... 68 lb/ft?), and while the car is in the air. The torque spec is important, it's very low, and most tire shops won't know to stop there. Most keep going to 85 and as high up as 110.<p>I highly recommend doing this yourself. Get a torque wrench and a socket that fits the lugs, and you will have everything you need. There's a jack and breaker bar in your trunk. It won't take you long, and you will know it's done right. You might need someone to help you to hold the brake while you do the front, but the torque spec isn't very high, and you can actually hold the wheel yourself while you torque it.