Five days is all it took for this Hoboken brownstone to go under contract for $350,000 more than its asking price. The six bedroom, four full and one half bathroom home was listed March 7 for $3.3 million. It closed last month for $3.65 million. “It was insane,” said Kaja Bolton of Christie’s International Real Estate, the listing agent. “I think we had 70 groups come through. That’s more like suburb kind of activity. But right now there’s not a lot on the market so we get a lot more people. Normally, 40 groups would be amazing.” The 4,000 square foot single family home on tree-lined Garden St…