Cash purchase/sales does not benefit a dealer more than leasing/financing but it is most worry-free way to make a sale because you don't have to deal with unapproved applications. In fact, most dealer would prefer making a sale on lease/finance, they end up making more money.
Back in 2008, I got $8000 off the MSRP plus 0.9% interest on my sedan finance purchase. They might still be able to offer discount in that number or greater, but I have not heard such low interest finance offer in Canada ever after that year.
The M3 is really an amazing car. I sold mine back in spring and quite often the idea of buying another one come cross my mind. This had never happened to any other vehicles I ha owned in the past. Just simply unforgettable.
Must stop eating..............