I personally wouldnt go a pro kit, because in australia we can use aftermarket parts so knuckles arent that expensive and to me one of the few worth while thing which comes to mind in the pro kit.
Ooops just noticed yeah you need to get a bearing kit, but you can get a bearing kit cheap....

You still have to upgrade the aluninium steering rack, not convinced the motor plate makes that much difference. You dont need the alloy rear hubs or the rear adjustable camber links. I got a car which runs great with stock hubs and rear camber links.
The adjustable servo rod is bling (i dont think ive ever adjusted mine). Cant think of what else comes in the kit....

The stock shocks which come in the pro kit break easily, you are better off with mini cvas or an alloy shock.

You have to buy a body. Note body can make a big difference to performance.
Best tamiya bodies are swift for the medium and for the long mini cooper and mito are good (i suspect the mito is a better body that then bmw mini, but i havent run it) out of tamiya's short wheel base shells i have only run the mini cooper.
Generally for someone new you are best going with a long wheel based car.

If you are struggling for cash some kits come with a cheap esc to get you started, note you have to check the kit to see if it comes with an esc its the same box its just sometimes it has a little flouro coloured sticker on it to say it includes an esc (you need to look for the sticker and check what it says a mechanical speedie is NOT what you want).