If it were me I'd go for the OS because it will be the easiest to tune as someone stated above. In that small truck I honestly believe that either of the motors will be too much power though. The RB will be a complete over kill not to mention the cost. Cheapest over kill would be the Red Dot off road version.
My 2 cents.
Team Shepherd USA:Nugget's Ranch Raceway
Primary Weapon: ?
Secondary Weapon: ?
Tires>>> I don't know yet
The JL EVO 3 "Tuned". the engine is hand modified by Eduardo Picco, sleeve has tear drop cuts and Exhaust timing has been changed, the engine comes already shimmed. unlike the other picco which is not modified.