If your money is tight do the brakes first. Because then you'd know what offset you need on your rims to clear the BBK.
Rims would be definitely nice as they will make your car looks completely a different animal. But it's gonna be very expensive if you want to do it right. Actually before you get any aftermarket rims, you should lower your car first. Otherwise it will look like 4x4. A lowered Z with stock wheels(even a mild drop) > A stock height Z with aftermarket wheels. Coilovers/lower springs + Camber/toe kits + wheels/tires = Sick = expensive = I will do it later.
