djr53,
The car will work fine with standard front knuckles and rear hubs. The main hop up to get is the bearings to replace all of the bushes and plastic bearing parts. I have not heard of anyone having heat bending issues with the front left knuckle.
You should take a look at the
http://www.rc-mini.net/joomla/index.php site and see what they have to say. Make sure you have a good read and then ask some more questions.
The ball diff is not always a requirement, but it is good to have. The universals would be higher on my list. 3Racing oil shocks or Tamiya's super mini cva shocks will work with a selection of springs. If your budget stretches then get TRF shocks however they are not really required.
You should build the car and drive it and then change things when you want too.
Not all of the bling is required to have a fast mini. The standard plastic steering does work, a couple shims and it is gold.
My thoughts only.
Regards,
Calvin.