I've had my G20 for about 2 years. Is it too late to de-badge it?

Depends on color and if you keep it indoors away from sun or not.

My car is silver and they came off perfectly after 8 years. You wouldn't know it was there. Darker colors maybe, two years seem pretty safe though. Try it and find out. If not stick them back on or have the trunk repainted if it really matters that much to you.