I’m interested in a 9mm subgun and the SWD + Lage seems to be affordable. Anyone have feedback on that setup?
My understanding is that the Lage uppers are preferred on those guns. The side charging handle comes in handy as opposed to the top mounted charging handle. And IIRC it slows down the rate of fire to make it more enjoyable to shoot. As well as adding more of a fore grip and mounting options. Those guns are on the more affordable spectrum of Class III, I think after that it would be AC556 or FNC 
I went with the M-11/Lage combo a while back and can’t say I would do anything differrently. My upper has the “tactical” bolt, bringing the ROF down to about 750 RPM. The gun is fun and reliable, though magazines are an issue. You are either saddled with the original Zytel mags with their associated feed problems or modified Argentine PAM-2 mags which require a fair amount of work in order to run right.
You can get into the gun for under $3K and the Lage upper for another $800, making it a very affordable SMG, and it is surprisingly accurate and entirely controlable. Not a bad choice, IMO.
I have both the m10 45 and the m11 9mm the m11 is by far my favorite of the two, as the m10 is a real brick. If you have a mac you cant go wrong with Richards upper and accessories
I own two and my son owns one. One of mine is converted to accept Suomi mags. My son and I use them at subgun matches and like them so much we have retired our other subguns. Mine is a "M-16 9mm and his a S&W 76. I cannot say enough good things about the Lage conversion.
Richard’s upper is the only way to go with an M-11. Makes it an Uzi 
Seriously the slower ROF and added weight really help control. I cant imagine firing my M-11 in its original form ever again, and haven’t for years.
Cant go wrong! Unless you stick with the original wire stock.