Hi Stew,
Good choice
I brought a load of screws from
http://www.modelfixings.co.uk but you can't get all the same size as the ansmann ones, I struggled with the gearbox screws and a couple of the countersunk ones, but they do have a good range of screws and some I just spaced out so they fitted. They come in seperate bags with the sizes on so it easy to start re-building with the right size.
Haven't bothered myself to run the associated wheel set up, the hexes are fine but I would recommend getting hold of a set of alloy ones as the plastic ones do tend wear down and bind up after a while. Get the 4mm ansmann ones and that helps get the car to fit in the scrutineering box at regionals and nationals.
Seeing as you brought second hand I would recommend getting some new nylon idlers and put them in so you know that you have the right idlers for the gearbox, Ceramic diff balls and some xray diff plates make the drivetrain pretty much bulletproof.
Other than that check out the X2C build tips thread for some good tips
