Nope. Bruv sounds like he's asking to spend perks to boost the spit beyond its rating so he can (presumably) run down ponies and 262s. And I'm saying, that you have a serious case of the dweebs if you need to make the best all around (non perked) fighter in the game even better.
Not beyond its rating, simply to its rating on 150 octane.
That said, I don't think it is possible for the flight model to be dynamically changed that way. I do think the Mk XIV should be remodeled to +21lbs boost on 150 octane as it needs to justify its perked status, but I wouldn't change any of the free Spits.