I can only disagree with you.
Running a hybrid just doesn't cut it, what modifications did his car have? I run a Microtech ECU, modified head, 270 duration cams, hybrid turbo, 510cc injectors, paddle clutch and this is close to 180hp and has been for some time without any problems.
I've got two of these cars and one GT, but I have to agree in one sense, they're reliable to 180bhp if they're well maintained - mine certainly is. The key to these cars is rich AFRs, sounds like your friend went through four engines to find that out.
From a power output perspective 80-100% (Or more = AkisGTti's 255hp) percent performance increase, these are just as reliable and impressive as a high powered 4EFTE. Perhaps more impressive being over 20 years old and missing a cylinder.
A member recieved a email recently from a guy whom used to work for Daihatsu, apparently an F1 team of the era purchased 3 CB80 engines for development. They were told that briefly over 900bhp was produced. No real evidence to back this up though, interesting.