You will be very happy with the NB48, the new shims do come in the kit as long as you buy direct from Tekno or from a distributor with fresh inventory, if its an old box sitting in a LHS it may not have them, in which case email tekno and they will take care of you guaranteed. You wont find better customer service than Thomas and Zac.

As for the LRC brace, not a necessity at all, I have them and don't run them every time, its just another tuning option not a necessity. The only thing you should buy is an aluminum servo horn, the only reason they aren't included is because it would add $60 cost to the kit to include all 3 spline types.

Regarding the brakes, I also spent a lot of time trying to get my brakes more progressive and have since done it but spending a morning solely focusing on the brake linkage and adding fuel tubing/springs etc... Point is, you can make them work to your liking either w stock parts or you can go mugen pads or some guys run the kyosho rotors and pads, all preference.