The GOP candidates who made it through the invisible primary (the months before any vote has taken place but contenders campaign like crazy) and lasted through Florida can thank super PACs, the shadowy political action committees that can take unlimited donations from corporations and rich donors. Once the primary ends and the general election showdown begins, get ready for super PAC spending and donations to skyrocket for both parties. After yesterday’s Federal Election Commission filing deadline, we can now attach concrete numbers and faces to the dark money fueling the 2012 election.  Here’s the scoop on the super PACs you should keep an eye on for the rest of the race (we'll be updating with more stats throughout the day).