Just a comment on the chassis tweaking.
I have built two PRO 4 kits. Mine which was one of the first batch form the UK distributor Mirage, and my Nephews which he got form a racer at the local club a couple of weeks ago (Still sealled).
While building the second one I noticed how flat all the screws seemed on the bottom of the chassis. When compared to mine which were raced quite a bit. This always made my chassis lift up one corner when put on a level surface and know matter how I retightened the top deck it would never sit perfect. I have now countersunk all the holes slightly deeper and the chassis sits perfectly flat, in fact both of the cars have no tweak. (even after some heavy crashes.).