As an example (can name names or car)...

(Not a cossie motor)
2.1 litres,
4 cylinders
8.7 CR,
Special designed pistons,
97 RON fuel (super),
Water injection (no additives),
Wideband lambda
EGT fuel control,
Motec ECU

840 BHP (With engine reliability - transmission is another matter !!)
I have seen this on the rollers and engine dyno ....