well, your'e gonna pick up proly about 6 to 900 fps speed, in a sub2000, over your 5 inch bbl glock. plus if you do it right, you can put on a light, laser, dot site, and just about anything else you need, all at one time, on the sub. i did it, and it was fun, but they do run very dirty, and if you are a lefty, go with a beretta, to keep the ejection port right out of your face, like the keltec does for lefties. also with that tube stell buttstock, it is hard to use the stock sites, you really need to get something up there higher.