That thing isn't even broken in yet.
Originally Posted by GotMirage501
I don't know the thickness spec of 2019 brake shoes. But I'm sitting here with a box of brand new, OEM 2015 Mirage brake shoes in front of me. The thickness of the friction material on these is 3.5mm...or about the thickness of 2 nickels. Here's the service manual spec for 2015 brake shoes...
...my rear brakes were down to 3.2 mm
If the 2019 spec is anything like 2015, Mirage brake shoes with 3.2mm of friction material thickness are pretty much brand new.
As for your heater core...read THIS post.
My heater core is basically where yours is right now as far as heater output. It's fine 363 days of the year. I would rather keep it like it is than have my dash disassembled. If I really wanted to fix it, I would try flushing it out with a solvent first (which is not something a dealership is going to do). Living in Virginia, I wouldn't worry about it. But if you want to get it on the record before your warranty runs out, consider calling Mitsubishi directly (as described in that post I have linked).
View my fuel log 2015 Mirage ES 1.2 manual: 52.2 mpg (US) ... 22.2 km/L ... 4.5 L/100 km ... 62.6 mpg (Imp)