ok so spacers are used to push out your wheels to: 1-give yourself a wider stance (equals better handling,) 2-to make their wheels flush (aesthetic purposes,) 3-to clear suspension &/or brake components. your stock studs will suffice the majority of the times. usually people only need longer studs if they use slip on spacers (which arent recommended, research why.) fender work is usually only required if your car is lowered and youre running bigger (both height &/or width) lower offset wheels. but @ stock ride height youre still going to have fender gap so you can go pretty big on both wheels and tires.. but it wont look good... another thing to consider which i see you did inquired about, is the dimensions of the tires.... choose your wheel size first, and then you can play with the tire size, going bigger or smaller as required to make it fit.
also, i agree that youll want to go bigger than 7" width. 8" front & 9" rear is a good start. as well as youll want to go much lower in your offset, 15-20mm seem to be good numbers to work with. just browse thru everyones set up and see what sizes their running & what spacers or fender work it mightve required.