MUP is a bit more involving. It includes an HK-style bending jig and generally needs a little planning ahead. Instructions are next to absent. But as far as buying one, it's no more difficult than P80. The 1911, however... How do you people even figure it out. The bewildering array of vendors, and which one is trustworthy? Are there any gotchas? The rails are not pre-cut. Isn't machining those to the required precision absurdly difficult?