Well, siliconing is replacing the recess (found in YoYoJam yoyos) with a certain substance for unresponsiveness. If you want to silicone the FAST, then just watch this video:
Shmooving: Is like a series of recessed around the response area. Meant to reduce the actual surface area that touches the string while in play. Some people might actually put silicone in these recess to customize the response.
Hubstack mod is commonly used on a FH0, so I’m not sure it can be done on a F.A.S.T 201, but generally, you would use this kit: http://www.yoyoguy.com/PN/MR03/Yo-yo-Upgrades/FHZ-Stack-Kit
Weight rings: http://www.yoyonation.com/home.php?cat=272 Are used to give more outer weight like YYJ metal rings do, giving it more spin.
Sating Finish: http://www.yoyonation.com/talk/index.php/topic,3903.0.html Is usually done to give yoyos a smoother finish to gove it more grinding capabilities.
Thats all I could find. If I find more things, I’ll be sure to let you know!
Have Fun Throwing,