HV-Maxx 4.5 or MM and 9xl?

[suicideneil]

Intriquing. The one thing that gets me though is gearing the two systems. In 12-13lb truck (IE:mine), I need to gear the HV4400 at 30:1 using 14.4v. Any higher and the thing just gets slower and slower, and tries to pull too many amps from the batteries, hence why a cell in a pack went pop. With an 8xl however it seems you can gear much much taller, say 15-20:1, using the same 14.4v, and although the motor may get warmer, it doesnt toast your batteries or speedo (usually anyway).
Is this simply because the XL motors have more torque for the same voltage/amp draw/kv rating? Its mainly like trying to read Irish looking at the equations....