Installation of DSC module

I had a DSC module installed in my 2001 BMW 530 I sedan recently because the anti lock break light symbol came on ansd the speedometer turned on and off at the same time. My questions are these.

1 What does a DSC module usually cost and what might be the time/labor chargeto do the job (i.E. Major job?)

2 Would the installment have anything to do with disrupting the motor oil (i.E. Having to drop the oil pan or filter, et al) because since the job two weeks ago, I now notice small drops of oil at the cwnter of the oil pan and on my driveway?

Thanks in advance for your response.

-jerry