The mad engine builders in Norway called Ruud Racing have built a Cosworth motor rated at almost 800bhp, now that is scary stuff
but in general the Cosworth motor is very good. I have a Cosworth engine in my garage waiting to be rebuilt and it will then go into my Ford MK 1 Escort, it should be good for close to 400bhp so I can already forsee some nice sideways action
There is a mountian of information to be found on the Cosworth engine at :
http://bbs.turbosport.co.uk/
http://www.passionford.com/