I am also building this chassis although my top plate matches the bottom chassis. I decided to use factory grey bulks and RPM arms with the true track rears, the set rear toe angle is fine with me, I have had a lot of problems with my old Tmaxx stripping the screws out of the bulk, even aluminum. I am wanting to try to keep weight down as much as possible as well.
I just purchased everything I need to put together a new CD using a 46t spur. Also using the RCM mount. I still need to have custom center shafts made to fit the Emaxx Sealed diffs I am using.
It wont be extravagent like yours but it will be fun. I also plan to run the MMM 2200kv System on 4s and occasionally 6s