On my Pershing build I did not use that 'metal tray', and I cut the speaker box down so the battery could slide back giving some room for the wiring and connectors. All Tamiya connectors were eliminated, splicing the DMD/MFU leads to one battery connection ... using a single Deans connector. And, on all my Tamiya tank builds I hard wire the motors in, so there's less connectors in the way.
Soldering is so much more fun!
- Jeff