Much. Note that my P-47 experience is limited to the bench so far, but the 10x8E on the Park 450 pushes WAY more wind than the stock motor. It seems ready to take off at about half throttle or so. Balancing the prop is a MUST, though, as the two 10x8Es that I have were both way out of balance, and vibration kills power output quickly on these motors.

I plan on maidening it early next week to prepare for some flying with buddies on the 25th. Always bad karma to maiden a new bird in front of friends

If you're happy with stock, you'd be pleased with with the Park 400, I think. If you want a bit more power, the 450 is up your alley.

If you're looking for good vertical performance, though, these aren't a match. I'll see if I can write a more coherent review after the maiden.