Raptor -
XVI
1) It would be 25lbs not 21lbs boost.
2) Perk it and it becomes another AH hanger queen. It may be a good allrounder buts it's nowhere near being good enough to survive in the MA perked.
3) WEP only lasts 5 mins then your back to a standard 18lbs. Interestingly Spit pilots routinely exceed the 5 mins 'advised' NOT mandatory WEP limit. In one case for over 30 mins.
Merlins were very robust motors, on the rare occasions a Lanc would lose one shortly after takeoff it was unknown for the pilot just to push the other threes to the 'stops' for the rest of the flight.
XIV
Should be given 21lbs to make it worth its perk price.
XII
Same as the XVI, would hazard it wouldn't be in the top 10-15 speed demons, and thats its main attribute. Was for chasing down early model 190's, not D9's or late model 109's that are all free in the MA.