i'd have to guess that tint would probably win in a poll of what people do first when buying a car. But really, what is your budget? Do you intend to keep the stock wheels/tires? Or are you going aftermarket? What is your end goal? Track machine or street sleeper? Going to start with cosmetic or performance? Again, what is your budget? There are cheap mods and expensive mods.
Here's an under $30 easy mod that will get you
interior dome light LED's Took me under 5min to install them and they look great IMO.