I am wanting to install a leveling kit on my '04 F-150 lariat s-crew. I saw another post regarding a similar situation. However, There was never any mention of the size of the spacers used. I was thinking about going with a 2 1/2" in the front with the 1" rear blocks. Has anyone seen what the best combo as far as lift is? Also, with the 18" wheels that are on it, what would be a good tire size upgrade, with no rubbing issues?