An extended magazine would give you a bit more bullets, like 45 for a 30 regular round SMG. Reloading owuldn't be much affected, just slightly, same with drawtime.
Drum mag would make reload more lengthy, aswell as possibly the drawtime a bit longer. You would also have more bullets than with an extended mag.
Extended 40/200 instead of 30/200. No other change
Duct taped double 30/200. Faster reload speed.
Drum mag 60/200..... Weird.. no other change (drum same reload speed as standard...maybe balancing issue?)
Source
http://www.youtube.com/watch?v=EfvfIXTFWJc at 1:22
EDIT:
To sum it up: everything comes with a trade off.
Saw your post after I posted mine.
For some reason Drum doesn't seem to have a trade-offf
Also Silencer has no trade-off.... so confused as to why not...
Oh um same vid 1:17
And front grip, little tiny extra stability but halves equip speed. :huh:
1:20