trust stickers are worth 200hp each, and the fuse box that they painted mardi gras yellow is worth 20hp.
To be serious, If we could tell you what it's power output is just looking at a photo we would be charging for that service.
As was mentioned above that top radiator hose is rooted (top of radiator has dried coolant on it that looks like it has had stop leak put in it)
Best bet if your looking to buy it go into ERD and get the guys down there to do a pre purchase inspection and if you want power figures and are willing to pay book it in with Sean over at EFI and get a power run done.
So many people ask this sort of question on a forum how about asking the owner where he gets his work done and check with them what has been done and if it has been dyno'd.
Is the owner a member of this forum if so check previous posts to see if the car has had an known issues and if they were solved here.