Associated makes some good stuff. I'm not really fond of electric myself so I'd be more than happy to plug the MGTs, but they're nitro only right from the box. There are conversion kits for the MGT 4.6 though. They do have the RC10T series, only 2WD but they'll handle grass quite well. Their durability is quite excellent. I have an NTC3 running a .18, and I run it anywhere but on the pavement. Rally car, basically. Even that can handle grass up to about 3/4s of an inch deep before it beaches, and I have yet to break it. So you'll be happy, durability wise, with any AE you choose.

As for brushed...don't. Spend the premium and get brushless, or go glow. Brushed motors just don't have the power or longevity to be worth it, and they use more electricity to boot.

On the AR7200....Not sure if it will fit in the radio box. Also, the range is a bit excessive, a parkie Rx like my AR6110e is perfect for cars. Nice, small, durable, enough range to lose track of which end of the car is pointed at ya. Easy to waterproof, too, their small size sees them easily slip into balloons.