Questions about leasing a C450 AMG or C43

I’ve always leased BMW’s, but I’m looking at my first Mercedes lease. Can anyone tell me what percentage off MSRP I should be negotiating on the C450 or C43? Would it be easier to get a deal on the C450 and does Mercedes do the “executive demo” like BMW does? Also, what are the residual money factor on 36/12k for these cars? Thank you all for the help.