Which Controller for My Application?

[RC-Monster Mike]

I am right there with you! I don't think you will get a 30 minute runtime with 4000mah packs without a battery change or so. If you use high enough voltage, you can get a pretty good runtime with 4000 mah, especially on a short track with low gearing. For a 30 minute main, you will also have the challenge of keeping the motor cool (think fan, heatsink etc.), especially in the summer. A large motor should be in the cards (larger than the "s" Feigao or basic xl). I am thinking "xl" or a nice 1940 Lehner.