Power isn't an issue for IC. I started flying 5kg, 2m models with a YS FZ140. Now i'm using the YS DZ175cdi and still 5kg.
The DZ185cdi is more powerful again and the models are still 5kg. Power to burn.
Having not flown a bipe pattern ship yet, i don't know what benefits they have over a mono plane, but they cerainly look cool.