[BP-Revo]

Nah...I think blissfully unaware is best. ;)

The close ratio 2 speed will low 2nd gear and make it close to first. A stock revo has the gear split about 60/40, meaning it will do 60% of its top speed in first, then second will get the rest covered. The close ratio will bring it to something like 70/30, which is better since you want second gear just a tad taller so it increases top speed when it shifts but doesn't strain your motor or ESC or anything. This way, you can gear your Revo a little low so the motor is working very little in first gear but still gives you the same (or even higher) top speed in second. This also increases run time and decreases motor and ESC temps.

With a 1950, depending on the turns and voltage used, you should get 50mph out of it quite easily if I'm not mistaken. That should be more speed than the 18TM and have probably 3x the acceleration (limited mostly by the truck wheeling) and 25x the torque too.

For the ESC you have 3 options:
MM - will limit the motor and cell count some what.
Quark - expensive.
MMM - have to wait.

For motor and voltage, you can run a 1950/6 or 1950/7 on 4S lipo, a 1950/7 or 1950/8 on 5S A123. A 1950/8 or 1950/9 or 1950/10 for 5 cell lipo or 6S A123. It depends. Just shoot for about 40000RPM with whatever combo battery voltage and motor turns.