I never had the wheel nuts come undone on the cat with core RC nuts or the durango with the kit ones.
I sold my cat because I was tired of it eating gears (although resolved with more cost and metal gears), it eating belts at £7.99 a go, I found it broke wishbones quite easily, I hated the mesh mech also. I also found the parts were more expensive than other cars. Schumacher could of done themselves a lot of favours by making a shell which went all the way down the sides so it didn't look silly without an undertray
I've only run the durango 4 club nights so far and getting on really well with it. It feels great to drive on polish floor and carpet and jumps amazingly. I haven't done a lot with the setup yet as I've been getting great results out of the box and haven't broken anything yet lol
I don't find it ultra agressive at all. it's nice to drive and the geared diffs are a joy. I found once you tried to ajust the cat diffs they started falling apart all the time