Was not sure what to suggest based on what wass on hand... but looking at the trucks online to see what they were I wondered if those SC style motors would just blow the belts off after a while.

Fritzl65,

As a chassis, for wife and kids, the SCTE 1.0 is a good choice these days.. tough as nails, easy to find parts for, and above all just a cheap buy in. You can also do well with the stand by of a slash or stampede.

Run what you have for now except where you have the motor pulling too hard on the ESC (no need to fry the gear). But keep an eye out for deals out there, not sure what the parts support is on your HPI trucks now, but I imagine it can be slim pickens.