Would you consider changing your nickname? It is a little, um, unsuited for
a guy who now owns such a formidable air compressor :-)

Whether you plug it in or whether you hardwire it using flex conduit will
be decided by how soon you plan to move, and if you think you'll be sharing
that circuit with another machine. If, for example, you may want to have 2
different machines plugged in when you weren't using shop air, you might well
want to have it on a plug. If you wanted, you *could* knock out a hole in one
of your outlet boxes and hardwire it in there, splicing in a 3-wire pigtail
so both the outlet and the air compressor would be connected, and just use
one or the other. It isn't up to code, but when you move you'll take your
air compressor and just pop in one of those 3/4" knockout plugs and then
presto it'll be back up to code. A one-man shop can run on the assumption of
one machine at a time in my opinion.

Hardwiring it in flex conduit is cheaper than buying 12-SO3 cable and a 220
plug, as you'll soon find out.

Grant