Have been doing it on a greased pan, does anyone know how much difference a pizza stone would make? Is my oven hot enough to get the classic Italian style with a crispy base that cooks in about 4 minute flat?
What other must have equipment should I invest in?
1) If using the same dough, baking pizza in a grease pan vs using a stone will give you a different result. The grease pan will give the crust more of a crispy, fried, oily, pizza crust similar to a pizza hut pan pizza while baking it on the stone will yield more of NY/American style crust like a pizza hut hand tossed crust.
As far as the difference you are looking for, are you referring to oven spring? How puffy the rim will get? A pan pizza is usually baked at lower temps and for a longer time and will have a more dense, tight cell structure look to it. This doesn't mean that it's necessarily dense or heavy in texture but just in look. Pizzas baked on a HOT stone will tend to have a bit more aerated look to them.
Not sure if your oven will give a 4min bake or not. The time of bake is dependant on the temp, and at 536F each oven can bake fairly differently. As a guestimation, I would say you are likely going to get closer to a 6 min bake in your oven which should yield pretty good results. You can get a 4 min bake if you use the broiler element.
As John said, a classic italian style pizza (Neapolitan) would require much higher temps and be baked for a much shorter period of time.