In my opinion....
K.I.S.S. = Keep It Simple Stuipid
is the moto I go by, so that being said....
We have 3 "official colors" right? (Bira Blue, Yellow, White) then we can do it two ways:
Option A - The BCR race car can pick one (or two to be use as stripes) of the 3 colors above as "based color" for their race cars... then the stickers logo (maybe with grey outlines too) in the same design and positions in EVERYCARS. That way it give racers choices, but still stays within the same "looks" as a team.
-OR-
Option B - Fixed one "based color" for everycars, so it will look like the same identical team just different cars. That would stay true to the whole team "uniform" colors, etc.