ive just got a makita 18v 1.6aH impact screwdriver with the 1/4 hex to 1/4 3/8 and 1/2 square drive adapters off ebay, undoes the wheelnuts on the 205 (85nm) a piece of piss. i've already got 4 batteries and a charger as they are the same as my chordless drills so the body on its own cost me just over £50 iirc.
ive also got a bosch 110v big bastard for the really tight stuff, crank pulleys and the like.