i'll be short with my wordings,
195 tyres of GIII's, 15 " branded design alloys,
and 4 set of wheels and 4 set of alloys is good 2 go, with new tyres in place, and if you are in a good living area, you won't probably be having any punctures for the atleast first 6 months (i assume), and if the NEWLY bought spare wheel is lying back in car dicky, unused, the rubber will eventually start to deteriorate, same way the tyres deteriorate in the tyres shop if they lie unused.
Shop Wisely as i said, and if you are still willing to shell out money, i don't mind you buying 5 sets of wheels.
@ cooldhaya :- congrats on your 5000 posts, you are almost there.