[SEE]

IIRC, Rolls Royce considered the advantages and disadvantages and felt that the carburettor system was better for acheiving max HP from the Merlin.

The Luftwaffe fitted a FI engine (can't remember which model but one that was already in service in one of their bombers) to a captured early Spit and, from the accounts I read, Luftwafe pilots really enjoyed flying it. I am pretty sure It was sent to the USA at the end of the war but was written off in an accident.