If that is the new razorback version (http://www.hangar-9.com/Products/Def...ProdID=HAN2790), go with a 20cc gasser like the DLE20. While H9 state that the evolution 15cc gas motor is fine, you'll notice in their promo video that they actually state that they are using an Evolution 20cc gasser themselves on the plane that is shown flying.
The other thing to note, is that specific plane is a little bigger than previous 60 sized P47's at 67" wide (the old bubble top version was 65"), and with a cowl that size, you'll fit a 20cc gas motor in and it won't even be visible. Not to mention cheaper to run, BUY, giving you longer flight times, no oil mess like nitro etc etc etc.

Also, as for your question "So theres no real difference between gas and glow 4 strokes of the same size?", as a DLE20 has the same capacity as a 1.20Ci motor, you'll have fun finding a 1.20Ci 4 stroke nitro motor that produced the same amount of power as the DLE20 does. The DLE is a right little brute of a motor. And the DLE20 is normally cheaper to buy that a 1.20ci nitro 4 stroke motor.