A 50% share in a used HK Mark23?
Probably going to want some big pants and LOOONG shirts for IDPA.
Just remember the ammo will outcost the gun long before the gun wears out, so don't be shy about spending a bit more to get what you really want.
Glock 21sf.
The M&P45 is the best choice in a sub-$1000. .45ACP pistol for IPSC (Production Division) and IDPA.
In my opinion.
With RTF, got my vote. I love it.
There are no decent 45's under a thousand bucks. Like it or not, unless you are only going to plug tin cans the rest of your life, you will eventually have to upgrade. Take your lumps, spend your money and do it right.
The only other option is the used gun racks or the EE where you can pick up gems for a song and a dance.