Had the Merlin been fuel injected like the DB's then they wouldn't of had the performance boost that they enjoyed. The Spitfire would of probably been slower than the 109.
It's as simple as that, though I have the feeling you're going to pointlessly argue this now.
At the end of the day, the RAF won the Battle of Britain with Merlin engine aircraft and the Germans lost. Wasn't a score draw and the Germans certainly wanted to win.
I don't believe either of the aircraft were the best fighter (nor the P-51 for that matter!) in the ETO.
Oh and you could of at least had the dignity to of watched the video before commenting about it! Do yourself a favour and watch it through the link I provided or fire up the VHS.