arms rarely break but they do eventually. keep a set of front/rear arms, front shock tower, cvd rebuild kit (i've had a cvd pin break on me, but that car was about a year old). front bulkhead. i also have a spare set of caster blocks just in case. oh and have some extra rollpins, or better yet, just upgrade to rear hexes and use the solid axle pins. get an extra idler gear as well.