"bigmaster", I keep wondering too, so I can understand your sentiment 
Pakistan Customs is only going to assess a vehicle straight off if it is an Asian make. For all practical purposes, if the vehicle is a non-Asia make, the original manufacturer's website is rummaged for pricing and if that doesn't work, the manufacturer is contacted for a price list. Since Maybach stopped manufacturing this labor of love, greatest chances are that Shahnawaz Pakistan is going to perform the assessment of value since they are a sister concern. Typically, Shahnawaz has a repugnant habit of declaring very high values. A friend of mine recently had a 2013 C-180 assessed for 3.6 million while he bought it in the UK for some 12,000 GBP. So supposing your value of $450,000, you could expect taxes worth some $500,000 due to a Shahnawaz assessment.
Hope this helps. Please feel free to put up any queries.
Fahad Bashir,
Assistant Collector, Pakistan Customs.