I had to do a lot of filing and stone work to get my Wilson Combat parts in my long slide 10mm. It took hours and hours of filing and fitting and filing and fitting. After that I had to go back and put the ceramic stones to it. They are not drop in parts by no means. I won't be doing another one of those for while. To put it bluntly it was a bi**h.
I built a 1911 in the early 80s using NIW GI surplus parts on an Essex frame. Talk about fitting parts! But when done, it was slick, and the slide was soo smooth you would think it was on linear bearings. Trigger just the way I wanted as well.
I learned I could buy a new Colt for less money.