Bear in mind that if you disable the indexes you need to rebuild them afterwards. Unless you're doing a huge amount of inserts/updates, the cost of the rebuild (and logging impact) will likely be more than any gain (if there is one) by disabling them
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability