I've had my 6 passenger Signature X for 3 weeks now. In the past I had family members complain about the seat belts. We are away now on vacation and after a 3 hour drive and a couple of 1 hour drives the same concerns. First of all the belts for all rear seats seem low going across the shoulders and bother everyone. I've ordered some seat belt cushion pads and hopefully that will help. More of an issue though is the attachment point for the middle buckets. They are actually part of the seat and not outboard mounted like most vehicles. For anyone of average size and especially people broad of beam they cut into your behind by your hips. My adult daughter even now has a bruise from it. Anyone else notice this? Otherwise love every other aspect of my X but this seems poorly planned by Tesla.