Bad OP! This topic will lead to nothing good!
By the way, the Gran Turismo series has long been considered the most realistic racing game out there, with the exception of car damage (which I understand will be incorporated into the full GT5 game). Polyphony Digital pride themselves on making the most realistic driving simulator ever and many people seem to agree, including the F1 drivers that actually train using the game!
I am not putting down Forza2--it is a fun game--but it has a LONG way to go before it can claim to be a more realistic driving game than Gran Turismo "in all aspects".