You will need to get "pass thru" or "Y" connectors for your 4-pin power cables if you need more. You can always add them later as needed. They can be ordered online at many places or bought at your local comp store!
As for the "shields" or metal knockouts, you do not "need" to remove them as you have seen, but I always do to allow better airflow. It's up to you!
Main DVD MM Rig:
CoolerMaster Storm Scout
AM3 Phenom II x4 955BE @ 3.6 ghz
Corsair H50 Watercooling kit
4.0 GB AData DDR3
GIGABYTE GA-MA770T-UD3P Mainboard
Western Digital 750GB 7200rpm w/32mb cache
Samsung 750GB 7200rpm w/32mb cache
Western Digital 1.0TB 7200rpm w/32mb cache
LG 20x DVDRW-DL "SuperDrive"
PNY GeForce 9800gt 1024mb w/Samsung 245BW 24" LCD
Corsair 620w Modular Power Supply
Logitech z-640 5.1's
Logitech Wireless Mouse
Win 7 Ultimate........