Carbon fiber is very light, so unless you put the tape on edge, creating lots of drag, you should not have to increase the power.

As far as the other items go, it will depend on the airplane. If you have lots of power now, the plane flies and climbs well, you can get away with adding a little more weight. Just remember that the plane will not perform as well when the extra weight is added.

The amazing thing about electric motors is that you can get more power by simply using a slightly larger propeller in many cases. Another way is to add another cell to the battery pack. Yet another way is to change the ratio of the gearbox.

Just changing prop size, cell count, and gearing willy-nilly will not work, though. You need to do it intelligently, or you will lose efficiency and/or damage the motor, ESC, and battery.

It's not as simple as swapping in a physically larger motor. If you change nothing else, a bigger motor will often result in your plane having LESS power. You also need to change the propeller, gear ratio, and battery.

The biggest drawback to adding a bigger motor is that it adds weight. Bigger motors often require bigger batteries, which adds even MORE weight. All the added weight needs more power to move it, so you get into a vicious cycle of adding bigger motors and batteries until the plane weighs a ton and flies for 30 seconds...

Suffice it to say, there are many modifications you can make to an existing power system to squeeze more power out of it.