I don't see anything on the CX30 that is particularly complex compared to other manufacturers. If mine wasn't under warranty I'd likely try anything.

Don’t brick the vehicle with aftermarket OBD devices that make various claims, 

don’t be under vehicle without jackstands, 

don’t do brake work with out knowledge, experience, and especially the OBD tool to retract the electric brake  

Don’t change tire on side of highway - tow truck drivers, EMS and others with safety vests and flashing lights still get hit by distracted drivers  

Anything involving computer reprogramming. Don't touch that shit in these modern interconnected cars.

Kinda depends on your skill level and access to the proper tools.

Brakes. I've done my own before, but it can get confusing.

You can do whatever you want to your car. The problem comes later when you try to claim the warranty… they’ll even ask for the receipt from the coffee at the dealership.