Picking up ML350 today, questions?

After a long debate between the MDX and ML, we decided to go for the ML350 gas, and are picking it up today.
One question I have is do you think there is more to squeeze out of the deal or is this pretty much it? MSRP is 56025. Got it to 50750 without customer 1, then used my fleet to get it to 48,750. No dealer installed Add ons. We are leasing for 30 months/15k. Acquistion is 795, and got the MF to the lowest of .00122 with autopay.
If I can do a little better at the last minute, who wouldn't like that? What are your thoughts? I know its a good deal but I always like to do my best.
The other question is should I get the service plan for a and b? It should be residualized at 60%, so my cost would be probably around 15 dollar a month.
Is service B at 30k or more? My lease will take me to 37.5k.
Thanks!!



