One problem related to front seat power adjust has been reported for the 1997 BMW 540. The most recently reported issues are listed below.
The driver seat creates a clicking noise and moves out of place (very minor movement) at numerous times (as in not in locked position) while making turns. Took to dealer and they want a fortune to check it out. The 540i only has 65k miles on it. It can be a dangerous situation, if the chair some how loses it locking.