Brakes!
Our '16 (bought NOS in '18) finally started making the wear-indicator noises, so I tore into it to have a look. Always interesting to see the new ways engineers have figured out to retain brake pads. I can be unobservant sometimes - I didn't immediately recognize the worn wear indicator as a wear indicator on first disassembly because I'm used to a giant wear indicator riveted to the back of the pad, so I didn't discover the worn pad until I had shrugged my shoulders, hand-reconditioned the rotors to break the glaze and knock off the excess rust, and went to reassemble. The interesting thing was that only one pad out of eight was actually worn excessively, and that kind of at an angle (toward the wear indicator, conveniently), so I'll have to keep an eye on it. Couldn't find my tube of caliper grease so I put antisieze all over the crazy little springy-slidey inserts. On the plus side (a big plus!), I was able to get the rotor hats off with a moderate amount of bashing - unlike on the 5, where I eventually gave up and got new used steering knuckles. I also like that on the 3 they've gone to the GM style of a two bolt connection from the strut to steering knuckle, which makes both strut replacement and camber adjustment far more convenient.
I ended up putting the original front pads back on and bought the $30 CarQuest rear pads from Advance. Figuring I'll order all new parts within the next few months, and possibly plan the job so I have time to take the front rotors to the machine shop if I so choose (used to be it was down the street, $15/rotor, and done while you wait - last time I went it was a few miles' drive to the shop, $25/rotor, returned with an extremely rough surface finish, and they kept them over the weekend plus a day or two - what's with that? I called all the area parts stores too, who all either lacked lathes or the lathe was broken or they had no one trained to run it, which has me wondering if there's a market for buying a brake lathe and getting appropriately certified to turn brakes for other people.).
An interesting issue I ran into on this car was jacking points. On every other car I've had, both front and rear can be jacked centrally with a normal jack, and usually from somewhere easy to reach. A RWD car can be jacked from the rear pumpkin, and a trailing-axle FWD car can be jacked from the weird L-beam thing. The MZ5 is a bit dumb because I have to put the front on ramps and then reach way inboard to the rear of the front subframe, but the back can be jacked straight from the ground, from the middle of the IRS assembly. Not so on the 3! They put the exhaust pipe going right under the middle of the IRS, and I'm not sure there's clearance for the saddle of the floor jack between the LCAs even without the exhaust there. I ended up jacking one side, then the other from the pinch welds whilst having fantasies of that crazy portable scissor-lift thing the Mighty Car Mods guys have. How do other owners do it?