As long as the unit is pre-charged, DIY installs aren't that bad. I've done 2 Pioneers at my home. I spent around $150 in tools.

Awesome, I’ve been considering installing a few myself but am not sure if that’s silly or not.

I’m mostly curious how these DIY units compare to Mitsubishi, which seems to be what all the installers recommend.

How do you get the pipes through the wall in a pre charged unit? Do they have two pieces connected by a special valve? I’m curious about how they keep the air out of the lines.

Pre-charge has one of two meanings here. Most mini-split units have the refrigerant in the compressor unit. After a complete installation, evacuation, etc, you open a valve to release the refrigerant into the lines.

There are also DIY variants where a fixed line length comes from the factory with either a vacuum or a refrigerant in the line. The lines have metal seals on the fittings that are ruptured when torqued down on the equipment.

Was there anything beyond the extra time/effort that made you regret going with a non-DIY model? I’m considering doing the non-DIY in next year or so.

No, not at all. I enjoyed it but my wife had a different expectation of completion date than I. My advice is to get the tools, don't shortcut, so that you have confidence at each step.

Stuff I had already specific to HVAC:

-R-410a manifold, gauges, and hoses.

Stuff I went out and bought:

-Nitrogen tank pressure regulator and hose for HVAC.

-Mandrel pipe bender

-Flaring tool

-Micron vacuum gauge

-A slightly better copper pipe cutter and deburring tool.

Stuff I rented/borrowed:

-Vacuum pump from Autozone. Free. It was plenty big enough for a minisplit.

-Full nitrogen cylinder rental from Airgas.

Things I'm glad I did:

-Used a wall mount instead of a pad for the compressor unit. Unit stays clean.

- Pressure testing with nitrogen. It's worth the money and effort to know up front it doesn't leak.

-Followed a more thorough procedure for vacuuming/drying which involves vacuuming down several times and flushing with nitrogen. I got a much better vacuum after subsequent flushes.

Thanks for the follow up! I understand completely. Somehow my wife stuck with me after more than a few significant home projects with misaligned expectations around completion. Re: wall mounting vs pad. Do you find noise transmission to be a nuisance?

I was on the lookout for it, as it was a concern of mine. I haven't noticed an issue. It's also mounted on an exterior wall of my garage. That wall lacks insulation but has drywall. It may be more of an issue if it shared a wall with a bedroom. The mount has rubber dampeners between the unit and the arms.