A 3/8" up to 100FtLbs will handle everything for the engine (except for the dampner). The biggest problem on aluminum engines is stripping bolts so I like a 3/8". If you want to torque the suspension parts I would get a 1/2" up to 250FtLbs. Most people just run the suspension down with an impact. Buy good quality used off EBAY, Snap-On, Mac, etc.
Also, get a click-type. Either a wind-up or a set type.