Um, sorry, but have to correct this:
For an iPad2 ONLY - If you are on iOS 6.x, you can selectively restore iOS 5.x onto an iPad2 IF you have SHSH blobs from both iOS 4.x (any version) AND iOS 5.x (any of the jailbreakable versions). Oh, and you can't have put iOS 6 onto the iPad2 via the over-the-air method. If all those conditions are met, you can downgrade an iPad2 to iOS 5.x from iOS 6.x.
This is only for the iPad 2, which you have, Sun King. The iPad 3 and higher can't do this (they never had iOS 4, so can never have the blobs required to downgrade).
Also, for any iPad - if you are still on iOS 5.1.1, you can re-restore iOS 5.1.1 using the methods outlined here: TUTORIAL - Re-restore IOS 5.x on iPad2 and iPad3 using redsn0w and SHSH Blobs, thus getting a "clean" install of iOS 5.1.1, ready for re-jailbreaking.
Just so's you know.