Well, both of these kits are very, very old. The Armoured car is still readily available and is also available with PE screens. The Panzer III is ancient, I have it myself. The detail is really oversimplified, molded on tools, etc. The wheels also have solid holes in them. The figures are somewhat dwarflike, as well. If you still want to go ahead, build and paint away, but you may want to hang onto it as a collector's item - especially since it still has the RiKo (Richard Konstam)sticker - they were the official importer in the 70's. Myself, I'm going to build mine with a few DML extra bits - I have way too many collectables already.
As for the SdKfz. 222, it can be built up quite nicely, the jerrycans should be replaced, and use PE or home made license plates, the kit ones are pretty thick. Unfortunately the interior is empty except for the gun breech, so either go closed with camo netting or foliage, or jam it up with a figure or two....I am pretty sure the wheel hub covers make this an earlier vehicle so maybe just go with Panzer Grey?