15x7 isn't drastic at all. as long as it clears your brake calipers. the +18 is where you come into problems. unless your trying for the hellaflush look you want to stay near stock offset, which with a 195/65 you don't seem to be. you want something more like a +40 or +45. the +18 will put the wheel outside of your wheel well without cambering the s**t out of them.
