I am noticing that most companies charge $40 - $50 more for a post-ban kit with muzzle brake, when compared to the price of a pre-ban kit.

How hard it is it remove the flash hider from a "pre-ban" kit?  Does it require a special tool, or is a standard wrench sufficient?  Also, would it be difficult to install a brake such as a Cav comp that would fit onto the threads?  

Please advise.  Thank you.

When I did mine it only took about 30minutes start to finish. I removed the flash hider, screwed on the cav-comp to the correct position, extended the hole driolled in the comp into the barrel my about 1/16", spot welded over the pin with a mig welder, smoothed the weld flush with a file, and touched up with a touch up pin. Mine is on a Colt upper that did not have a bayo lug. The ears on the lug can be ground or files off and touched up with a pen.

Cruizer