I've noticed no tire-wear issues with a spool. There's just not that much weight pressing the tires into the ground, unlike on a real car. The only thing you have to watch out for with a front spool is twitchy handling; some of my cars handle fine with front spools, but others wander when going in a straight line with front spools and no amount of suspension tuning makes it stop. Three of my RS4s have front spools, as well as my rear-motor XV-01TC, but my DF-03Ra and my FWD XV-01 don't handle properly with front spools. I can't say it's because of a forward weight bias, because the DF-03Ra has a rear weight bias and a front spool still caused problems. It's worth trying a front spool just because they're zero-maintenance forever, but if it causes wandering issues, change back to a diff with very thick oil in it instead; it will behave more-or-less like a spool when cornering hard, but it will drive more predictably in a straight line.