Nice video and great to see a Hi Power any day!
I have a FEG and Argentine FM which cost only $300 and $225 respectively a few years ago. Both work well and were bargains. As you said you can find true Hi Power clones like yours, although some models aren't 100% compatible. My FEG is the less compatible double action model but the FM is a true Hi Power in every way, even licensed by FN.
Great pistols and nothing fits my hand better. If someone stumbles across one under $400 these days I doubt you'll be sorry if you buy it.
The biggest issue with assembling an AR isn't so much getting the parts together right - it's getting the right parts together.
You'll remember the quality of a gun long after you forget how much you paid for it.
US Army 1966-69, VFW Life Member, Retired Geek