Nice one Zac. :)
If you want tank kits with all-in-one tracks like the M113 you built, try the Armourfast ones. They're intended for wargaming so the construction is very simple but there's more than enough detail to please a modeller, and you get two models in each box. They do some tasty subjects too: the M10/Achilles/M36 tank destroyers.
If you want to make your armour models look a bit more 'real', try dirtying them up a bit: in particular splash some mud (brown paint) over the tracks and suspension. Most AFVs are filthy within half-an-hour of going off road. Photos will show you the spray/fall patterns. It tends to be worse on the bottom run of track and the back section where the track picks the mud up and throws it upwards, then it progressively falls off as the track runs forward until the front part, where the track's going down again, is relatively clean. obviously this depends on the exact consistency and volume of the mud in question.
Oh and if you think the Sherman's built-up suspension and rubber tracks are fiddly, try a Churchill....
If the tracks' T-slot or rivet-peg setup isn't strong enough to hold it together (the Airfix Scorpion is a particular pig for this), one trick is to sew it together with grey cotton.
