The biggest problem is finding out which wheel offset you need. The wife got a set of "generic" Baby Moons and they are about a 1/4 inch from rubbing the fenders with the stock 165's but i have probably 2 or 3 inches from the springs. If you use an adapter you have to realize that it pushes the wheel away from the drum that much farther. The Super Beetles are harder to put wider tires on because of the Macpherson struts, the springs are sometimes too wide, you may need narrower springs. With the rear end you have to worry about the spring plates. With a 17 or 18x8 inch wheel i'd just about bet you would need wider fenders. They don't make a "dropped" spindle for a Super so your stuck with a dropped Strut instead.
With Porsche wheels they are closer to the beetle off-sets so they're easier to use.
Like "68autobug" said you can look for drums that are drilled for what you want or if you go Disc Brakes then you can buy blank rotors with your kit and have them Pre-drilled or drilled later for what you want.
'72 and '75 Super Beetle's