I have scim read the post so if there is stuff i have wrong forgive me.
I have tested the 3 normal traffic cars (Volvo V90, Audi A4 TSFI, BMW 3 Series) on this route (Red Start, Blue end)
Volvo Stats
Up Hill: 120
Flat: 125
Down hill: 134
Audi Stats
Up Hill: 123
Flat: 126
Down...