The only reason I got 60 amp esc's is because they where so cheap - $25 each at hobby king, and the lower amp versions weren't much cheaper. There really isn't a downside to using esc's that are too big (that I'm aware of anyway.) Better to have 60 amp esc's running cooler rather than 20 amp esc's maxed out if your using 20 amp motors. Also its nice to have the flexibility with the esc's to use them some day in other projects with bigger motors. I have some motors that look exactly the same (same size also) as the 20 amp ones, but they are 8 turn 4900 Kv, and using a 3S battery they can run 600 Watts, which is close to 60 amps. At over 54,000 rpm, they are totally inappropriate for tanks however. More like for ducted fan jets. Maybe someday I'll build a Messerschmitt Me 262 to provide air support.

Regarding the 2.4 GHz RX inside a metal tank not needing an external antenna - that is great news - I'm psyched! I have been dreading trying to solder another antenna. Also not having the delicate antenna wire tethered to the upper body will be great. You have to remove the upper half of the Mato Metal to access the batteries, and I can see the antenna wire snapping easily.

Russ