4 doors are rarer as most enthusiasts prefer 3 doors as they look a bit nicer. Although sometimes finding a nice 3 door is hard, and finding a nice 4 door can be equally hard as they tend to be treated a bit rough as the 3 doors are "the ones" to have.
Can't drive a gti slowley because they are revvy engines, for instance the valvers don't come on cam till about 2.5k, 2.75k revs. and peak power outputs on them are at about 6.5k. So naturally we all want to feel that, kinda like a drug.