OS 30V... i think it is suitable to Saverage type for high toque for climbing... truggy need speed....so ..you can try STS .28 3 port, SH 28 7 port (or 5 ports I can't remeber...)....
but the best choice is Nova 528 or RB 928.... most US truggy race top 5 also using this 2 type of engine.... great toque and high top speed... I still awaiting... anyone will import them.....if not.. i will order them.. around USD 319 - 359 exclude shipping....+_+!
may be you can wait Ninja .28....but still hvn't any photo and issue date....