I have been running a B.M.I. chassis since about a month before Cleveland. and have never broke a driveshaft or had my batteries fall out ever. I have both the 2mm (I use when I run rubber tires) and the 3mm top plate(for whenI run foams). we are still running it weekly without any of the problems you and JohnC have complained about :
the change was one that Tim and the guys from BMW/PSA came upon after they looked at the ackerman differances when using the stock steering knuckles to the Losi steering knuckles("C" hubs also)along with the nitro "swing rack" something most TC3 drivers have tried or are using. all they did was to find the correct place to mount the nitro steering rack. think of it as evolution on this chassis hopefully other enhancements will follow also.
as for B.M.I. rushing into the TC3 chassis without proper testing....I really don't see it from where I'm at....I have been more than pleased with mine. and I'm sure that I'm not alone on this point
I saw your B.M.I. chassis for sale on EBay...... maybe you should stick with a stock tub car. or wait for the TC4 you might be happier with one of those.
as for the Xray chassis I think we will see a better chassis along with a better top plate.
Keep it up Protc3!!!!!!!!!!