The estimated cost of building Louisville's new downtown arena has been lowered by $5 million.The project construction manager has announce a new estimate of $249 million, down from the original $254 million.Arena Authority Chairman Jim Host says one reason for the reduction is the diligence of the authority in keeping extra costs in check."The second thing is, I think the economy, even though it's not good, has helped us. Because I think we got steel prices that were less than the guaranteed maximum, we got concrete prices that were less than the guaranteed maximum," Host said.The multi-purpose facility at Second and Main Streets is scheduled for completion in the fall of 2010.