Hello, I'm travelling to from HK airport to Changan in Dongguan. How much will the Transport by the MPV.

I am afraid that I only take the direct cross border shuttle buses between the HKIA to Changan and the bus fare is around 160HK$ to 230HK$ per person.
I am not very clear about the MPV car's fare, but I know the Trans-island Limousine Service Limited Company provides such kind of service. So I think you may find more detail information on their official website.