Discount friendly Mercedes dealers?

[M135i]

I'm in the process of thinking about my next car. Local small dealership was very tight, almost awkward to discuss discount. Buying BMW there a few well known discounters (I got just under 20% off list on my M135i). So do Mercedes not operate this way, or am asking the wrong dealers? Looking at new PCP, possibly CLA.

Thanks in advance.

[M135i]

Thanks guys, I'll give it a try.