How is it strange that a supplier would turn you away. Of course they would...this no different than any other company. Can you imagine calling up the microchip supplier for Apple phones and asking them to work on the chip for you to increase performance or lessen heat when using heavy processing?
Morgan is the money funnel and going around behind their back and working with customers directly would no doubt be a heavy breach of contract. You are far more likely to find a separate company who can help you create a solution.
As it is, the M3W is basically a kit car which Morgan assembles in house, if all the suppliers let customers buy directly from them...people would just cut Morgan out and piece the car together themselves. Bad business.