I've got a used airtronics 94358. 200 oz./in. @ .10 $109 new, $40 at LH comes with spare gears

Also, a Blue Bird #631 w/NIP gear set to make it a #630 High torque $25

The 631 is fast and is good for th/br on a buggy or steering for an on-road car. They won't hold up on a MT or Truggy.