ORIGINAL: Echelon

What brand of servo's can you use with the included servo horns? The plastic and the alu one. I know they'll fit Futaba, but do they also accept other brands? What servo's are you guys running in the Truggy? Need to find some servo's for my car.
Budget: brake/throttle servo ~$40 and steering servo ~$100, but less is better, unless the specs arent that good. Thanks