Many Tamiya kits available on sale today still come with the TEU-104BK ESC. This ESC is perfectly fine for running brushed motors, but does not contain a BEC and its low voltage cut-off is too low for LiPo batteries.
The missing BEC is easily dealt with: either use "high voltage" compatible servo and receiver, or a cheap external BEC.
Fortunately it is also easy to modify the ESC to have a LiPo compatible voltage cut-off -- assuming you are able to solder a tiny surface-mount resistor.
