[Blue Bomber Man]

I thought I should point you towards an existing spreadsheet that is the culmination of years of research (I believe it is someones PhD thesis) that is availible on the web.

Just search for Pamvec on google, it should turn up an excel file. It is extremely customizeable for many things that you have already included but also for things like: various drivetrains (hybrids, electric etc), driving models, can specify design goals, or just input known variants. When I used it to model my current car it nailed its MPG rating and I used it to model hypothetical cars.