... authorities arrested someone involved with silk road... Bitcoin took a dive for a day or so... then marched up ten fold
So are arrests good for BTC growth then?

I was thinking the same thing. Of course we have other factors at play. I was already hopeful that after the 31st we would see a panic buy because people were just waiting to see if there would be a dump before then. It should be very interesting.
i personally see state backlash as bullish. the fact that the state is lashing out at us is evidence that bitcoin is doing what its suppose to do, its evidence that its working.