Signature Group, a full service commercial real estate firm, has negotiated the $1.6 million sale of 315 Greenwich Ave. and 39 Selleck St. in Stamford's rapidly developing South End. The buyer, Extreme Auto Body & Auto Repair, will move from its nearby Stamford location, expanding its business into the one-story industrial buildings, which measure 5,739 s/f and 4,000 s/f respectively. The adjoining buildings occupy a single, half-acre tax lot. Signature Group vice presidents Bobby Gillon and Andrew Carney represented the seller, BonCap Realty, LLC. Don Corbo of New England Properties represented the buyer.