You’ll need a radio, servo, battery for the car, charger & batteries for the radio.
Oh, and paint.
Most places do kit deals on the other bits you need, so you can buy them as a bundle.
You’re looking at around £80 for that lot.
It’s also worth getting the bearing kit for that car at the same time, as the kit comes with bushes with are OK to get running, but bearings are better & much easier to put in at initial build. That’s probably another £6-8 or so.
Regarding assembly – Tamiya instructions are excellent & it basically all screws together. I got one a few years ago & built it up over several evenings – realistically you could do it in a couple of evenings easily.
The hardest bit for me I found was filling the oil shocks – they only just about provide you with the the correct quantity of oil, so you need to be careful you don’t overfill one shock (or have a spill) because then there isn’t enough oil for the other shocks – I am not entirely convinced mine are all completely full.
Here’s mine:
DSCN8525_zpsu2hb6jtr by STW stumpy01[/url], on Flickr