not sure on what the kits are like, but any body kit is a bolt on thing, not double sided tape
as for spraying, ive never actualy had it done, but when i asked about a full respray once for a standed factory finish, it was around a few 1000.. so id asume that skirts, rear and front bumper, would be around a couple 100 each? sorry i cant be exact, but i figured better to give ya a ballpark figure anyway