I don't know whether the manual mentions putting grease on the crown wheels. Get some good grease like Tamiya ceramic grease and your transmission will last a lot longer. Also don't worry if it feels a little tight at first once you've shimmed it. It loosens up after a bit.
If you haven't built Associated shocks yet make sure you feel a "click" when you insert the O-ring assembly or your shocks will dump their oil.
Other than that make sure all the suspension part drop freely under their own weight without shocks on the car. I also always replaced the top front shock bushes that attach the shock to the shock tower with the screw and plastic bushing from the B4. I always had the feeling that if the arm goes then the shock doesn't break quite as quick.
Have fun building it and use proper tools
