Spool vs. One way
I just got an HPI Pro 4 Hara and it included both a spool and a one way (no front ball diff though). On my previous cars, I only used a front ball diff. I usually race on asphalt with low to medium traction (though I may race a few times on carpet over the winter).
Sorry for asking something that has likely been discussed previously. Can someone post a brief summary of when or why to use the spool versus the one way? Also, are there any circumstances where a ball diff would be the best choice?