i'm pretty sure a 4" rear lift spring up front would be huge in the front. it all depends on shackle lengths and drop of front spring hanger. i know there's guys runnin' waggy/stock toyota rear packs at about 6-7 leaves, and they get around 7" of lift with 2" dropp hanger and 1.5" shackles. if you kept the front spring hanger at stock height, but had a longer shackle, and the 4" lift springs you might be good, but then your pinion angle sucks. it's going to be big either way.
