Crime statistics were much higher in the 80's when the mafia was stronger, but it's unconnected. The 80's were violent , because of the explosion of cocaine and crack and the subsequent turf wars to control their distribution.

Certain mafia-saturaed neighborhoods, such as Melrose Park, were certainly safer then, but the overall trend is in the opposite direction.

As far as bad lending practices and swings in the construction cycle, I think that's more to do with legislation concerning Wall Street than anything to do with the mafia.

Infrastructure tends to be better in states that didn't have a strong mafia presence, but there again I believe it to be unconnected. I think its just that the mafia had a stronger presence in older cities in the NE and the Midwest and in those places infrastrcuture is the worst. Also, theyr'e high tax states that have a hard time attracting new business to expand their tax base.