You have got to love all the contractor bashing.
Are there some unscrupulous contractors? Sure are, just like there are some dishonest cops. Not all of them though.
Most local contractors operate on a 10-15% margin. The "big boys" are higher, but that is to be expected. Higher overhead, more office staff, usually newer, nicer vehicles, advertising, etc, etc.
I am fortunate to know how the business runs, not just from the technician side but also from the office side. We give away a TON of jobs, and often cut bills, etc, simply because the customer doesn't feel good or doesn't want to pay. Usually we did nothing incorrect.
As far as doing the install yourself and hiring a contractor to commission it? Sure, go for it. But its kinda like buying a mower at Lowes and then expecting the local dealer to take care of warranty issues. He may, but you likely won't be at the top of his list.
You see, the reason for mark up on labor and parts is to cover the write-offs, the warranty that the supply house won't stand behind, the free-bee call to tell you the stat is set to "off". If a contractor is charging $100/ hr, the tech is making about $30/hr. The burden labor rate is around $80-85/ hr (that includes the truck, the tools, the gas, the office overhead).
If you don't like my recommendations that is cool. Mini- splits are a service NIGHTMARE- no one enjoys working on them. Sometimes, as I have stated, they are a good solution. I was thinking you all would go for packaged solutions since I figured few people on here have the tools (torch, vac pump, micron gauge, etc) to do the job, and fewer yet actually know how to use them properly. Perhaps I am wrong.
I stand by this though, a conventional split is always cheaper. ALWAYS. They can be installed in attics, sat on the floor or hung horizontally. Easier and cheaper to have repaired. You get SUPERIOR filtration with a LARGE variety of filters (including carbon to get rid of all those "garagy" smells). Not on a Mini-split. You can add an electronic air cleaner if you desire (not a fan, lots are), a humidifier, and on and on, to a conventional split.
Same song and dance for the packaged convertible units. But all that was heard was "Mini- splits ****, get a PTAC". That was not the point. The point is, explore your options. Mini-splits are not, in MY OPINION, a good choice for a working shop.
PTACs aren't either, but at least you just cut the hold, slide them in, plug them in, and done.
Old home Hot water retrofits- Go mini-split (these systems are not really common around here, and I tend to forget they are in some places).
Its like this, I have been to huge, gigantic churches that have 30 split systems and a couple dozen roof top units. You try to tell them a Chiller is the way to go......but often people are comfortable with what they know, despite better, cheaper, more cost effective solutions.