Yes indeed Farber. The fuel gave an increase in performance up to FTH and we want that modeled. If it's modeled with 87 then the Spitfire will be slower than the 109 below 16 kft, which wasn't true when 12lbs was used and thus the reason this is on post 1 zillion is because a couple of people want a slower Spitfire in game than what was represented in the BoB.
http://www.spitfireperformance.com/spit1vrs109e.html
There is a graph on spitfireperformance.com which shows a considerable advantage but I would like to see more official data than the one displayed before I could be sure about that. This is the one they have vs the E-1 plus other data, some of it official.
roll rate
Dive acceleration is not here but combat reports all state that the 109 got away comfortably. Steep climbing turns are the opposite in game as IRL where the 109 should stall first on a 120mph climbing turn.