Lear Siegler Holdings Corp. will move the...

Lear Siegler Holdings Corp. will move the headquarters of its automotive parts supplier group to Southfield, Mich., from Santa Monica, in spring, 1988, adding 150 jobs . . . Argo Petroleum Corp., Santa Monica, said its reorganization plan, filed in April, has been confirmed by the Bankruptcy Court . . . Federated Group, the troubled home entertainment and consumer electronics retailer, said sales for the five weeks ended July 5 declined 17% to $33.2 million from the same period last year, when the company offered a special sales campaign.