i would think so, but you wont have reverse, or at least i wouldnt use it with 4s....
if the tranny can handle a BB motor it can most likely handle some bl and lipo
the BB is only 2hp and BL can have more than that. I locked mine. With that much power of BL you run the risk of shredding gears when it shifts. If not that you could wear the nubs that the clutch in the tranny grabs on to to engage second gear.
I've been running the 3-speed for a while now with no problems. First with an 8xl on 4s and now on a 1515/1y on 4s or 6s. Dewmerz is still running the 2 speed on 4s in his Savage, but hasn't had time to run it for a while. The only thing that worries me on the 2 speed is the plastic 2nd gear. With the extra torque of the bl motor it shifts really hard. Hard enough to break traction on every shift. It's a bit of a handful in loose conditions, but I think I'll leave it until it breaks.