Sup everyone.... im new to the forums and its looking goood!

I currently own a astra vxr but not really happy with it because its a front wheel drive. Im looking to get a evo. A freind of mine knows someone selling a evo 7. Is there a big difference between the evo 7 and evo 8? Also whats the potential bhp i can take the evo 7 to by modding it?

Thanks