in FR I'd only open KJ on BU, maybe CO, and if someone openned before me, I'd definitely be wary of calling behind even on BU, I'd fold to tighter players. I'm definitely not opening KJ in anything other than CO or BU though (unless it was suited)

Position is a lot more important than just a few cards though... I mean I would open 53s on BU (in 6max at least)