Dropdown dependant auto population of cells

Hi there,

I am trying to create a comprehensive car data spreadsheet which pulls data into dropdowns depending on the value of several other selections,
its very hard to explain via a simple post so i uploaded a spreadsheet to help make it easier to understand...

One thing to note... i may add additional data to Sheet 2, so it would be great if the created dropdowns could pick up the additional data when added... you'll know what i mean after looking at the excel file...

Thanks for taking the time to help with this ridiculously hard call for help!

Best Regards

SWM