If you go SWAT, you will have to match a specific character in the movie - such as pauldron color, matching pouches and weapon. For deployed/police officer you can do what ever pauldron color/pouch combination you want.
In case it hasn't been said, thanks for posting the pic Ruggero (even though you've unleashed a ton of chaos and extra work for future SWAT applicants ).
http://www.greatlakesgarrison.com/
Register here and introduce yourself. Upcoming trooping events will be posted on the forum. Once you're 501st approved as a TD you can participate in the troops listed.
I emailed Lewis from Hyperfirm about modifying the barrel and is strongly against it. I can forward his email if needed.
Because of this I'm going to put my application on hold for the forseeable future till I can figure something out for the MG-15.
Bapty is the name of the company that modified the guns so they could be sent to Tunisia for filming.
More info here:
http://forum.mepd.net/index.php?showtopic=13418
If you're buying from an established vendor on here that makes pouches, backpacks or pauldrons they will be acceptable for SWAT.
Keep watching coverage of Celebration 7 later this week in answer to your third question.
Most boots made for TK/TDs come in white. Some do buy black boots and paint them white.
www.tkboots.com
The method you use to weather your armor isn't going to matter if it looks screen accurate. I'm not sure if anyone here has used an airbrush or not.