One id the thjngs i suggest is using the 4 rear structural mounts for the rear seats.
Get a high grade zinc oxide fastener, since they will be open to the elements. I thought I put what I ordered in my build thread.
I also recently had my harness retainer pop out while wheeling and ended up with a mud squirt on my barn door through the hole.
Oops.
I don't really do hard core stuff but my GX has had enough air time to ear a roundel.
I also taught my partner how to wheel in it and they had some oopsies after they were recovering from Chemo. Like taking an 18" deep pothole at 35 mph cause they didn't see it. The tire carrier was fine. My head getting slammed into the side windows, not so much.
I also highly highly recommend throwing some sound proofing in while you have it open. That third row seat is an amazing sound insulator, and it will be a lot louder if you don't do some sort of treatment.
I got cheap stuff off of Amazon.