Are you looking for one gear to cover both on road and off road? In my experience 23/83 has yielded me the best top speed. 17-19 with the 90t spur will be good for off roading, just check your temps. Or if you mixed it up for both on/off road, I'd say 17/83 will be a good mix of high speed and fun in the dirt. I've hit 46 and 55 with 17/83 gearing with a 2s and 3s respectively with my 6900 rustler. Might I suggest some decent 2.2 on road truck tires for doing asphalt runs. Currently I'm using hpi v groove onroad truck tires. They don't balloon up very much and they keep you nice and steady. They won't wheely, but they will spin you out of control if you give it too much throttle at low speeds. Anacondas however, will balloon, pull themselves apart, and will not keep your front end down. At high speeds, giving it full throttle will just flip your ride on its back. Just my experiences, I'd stay away from anacondas. Also you'll need steel gears in your transmission and I highly recommend the FLM trans case.