TexasCHLforum.com

I've cut at least 5 guns and gone the low-profile route 2 or 3 times (I have a lot of friends that ask me to do this stuff for them). In my opinion, you're better off spending the $20-30 on the low profile gas block - it is just so much easier/cleaner. If you use Loctite on the screws, they probably aren't going anywhere (at least, I haven't seen it yet).

If you go the cutting route, you will spend a lot of time cutting, testing fit with the new rail, and then realizing you need to cut off a lot more. It's time consuming and, in my opinion, not worth the effort when the alternative is so much easier. You will also need some bluing chemical to darken up the shiny shaved metal. The new rail and the stuff you put on it will do a good job hiding the home-brewed FSB underneath, but you'll still know it's there and that bugs some people.

You might consider doing both - throw a cheap low-pro on there, and then cut up your old FSB and stash it in a spare parts pile. If you ever have trouble with the screws (you won't), just remove the low-pro and install your hack-job part.