Do the PreKey mod(aka leveling kit using 07 and older torsion keys), then do either a 3" PA or Summit bodylift or a 4" Superlift. Steer clear of things advertised as 'leveling kits'...just causes issues with front end wear.
Both are good for 33x12.50 tires.
A real good friend of mine has an '08 that's bodylifted on 33's and she has no trouble getting past the warranty. I'd personally wait til it's a little older in life(like 30,000 miles) before actually lifting it. That way the little stupid bugs are worked out already.
If I were in your shoes, I'd do the PreKey mod, ford wouldn't know anything has changed, and I'd throw on some larger tires(idk what your wheel size is but you can fit up to a 32x11.50 tire if prekeyed). Call it good til those wear out, then throw on the lift and 33's.
'01 XLT disguised as a '03 Fx4 Level II.