I would look out for a used savox 1251, 1257, or 1258. They can be had for around $45-50 bucks used, or around 60-69 bucks new.. They have titanium gears and work really good. I use the 1251 in my minis and they are PLENTY fast. Speedtech has the hookup on the ceramic diffballs and servos. They know their stuff, and will lead you in the right direction.