Ref the weight of the engine.
Its always the total weight of the car and the weight distribution ,front to rear that counts.
S2000 engine in a Westfield 480 kgs less petrol, 52--48 split less driver.
http://usa7s.com/aspnetforum/upload/1090477673_IMG_0714[1]
http://usa7s.com/aspnetforum/upload/2131775772_IMG_0715[1]