Shop air dilemma

Unless you have a real reason for wanting 3 phase, I'd reconsider. it's not required as many have said and the cost of the extra line is probably a waste. I do have a friend that uses some pretty bad *** woodworking tools so your mileage may vary. Beyond that, I'm not sure what "car related tools" I would ever use/need that might require 3ph. Maybe a big lathe or mill I guess.

Large volume, big pump and CFM is your buddy. I run my blaster, a modified unit that looks like a HF unit, but is not, all day long. You don't need that much pressure for a blaster usually and media flow is probably more important. Is in my case anyway.

Even a 60 gal, 2 stage would be good. Bigger units run quieter though. I can talk with barely a raised voice (by my standards) while standing next to my 80 gal, 5hp unit.

Something to keep in mind, those 110 units where they say it's 5hp, aren't. It's not possible to get that much power out of 110. At most they are around 3hp. Does it matter? Not particularly, lots of people paint and blast with a 60g all day long, it will cycle more that's all. more cycling, less life.