[spenner]

Toby,

Hex drivers required are all metric...

Easiest thing to do is get the EDS set or something like that, it covers you for all sizes then.

Slipper and Diffs..

If i am honest i never had any issue with these, build them as the kit says and do your normal checks. Make sure you compress your car on carpet or something grippy and move slipper with your thumb. If it is slipping and the diffs aren't then it should not be an issue. Once set i have never really worried about mine indoor and outdoor.

I will suggest the Rudebits weights for the centre of the car, personally i run 30g but that is to personal preference. The car is very light so weight is needed. And it also helps to make the car feel planted.
For setups:

I think everyone is running very different setups but all with a similar feel, my car is very soft compared to most others i have looked at and felt. So it is a matter of finding what is best for you. Personally i would build to kit (i changed pistons) and then try, work from there to find what you like.
You will be looking for more steering and there are options available from Vega, DMS or the guy from Germany.