In reply to NOM
Most production car are arount 100bmp/litre, the impreza and evo are the exception, and no doubt there will be other others, look at the list you posted :
Volvo T5 250bhp from 2.3 @ 100 bhp/litre, 2.3=230bhp, 250 in not far above
Megane 225, 225 hp from 2.0 @ 100 bhp/litre, 2.0=200bhp, 225 is not far above
etc
i agree that that technology is moving on and maybe this estimate is beginning to fail as a rule, after all it's a while since it was told to me!!! But in its defence it still not bad.
With lots of re-enforcement and expensive parts, it is true that you can get lots more power from a 2.0, but the cost is so high, something like a rover/(Buick) V8 would provide similair power with little modification and be under less load.
Or in the case of the new Dodge Viper you could have a huge 8 liter engine and get only 400bhp from if???!!!!????
Actual figures are usually slightly more than this.
Volvo T5, 250bhp from 2.3
Megane 225, 225bhp from 2.0
Mazda 6 MPS, 260bhp from 2.3
Vauxhall VX220/AstraVXR, 220bhp-230bhp from 2.0
Any number of VAG cars, 225bhp from 1.8
etc. etc.
A mere 200bhp from a high-pressure 2.0 Turbo these days, is sub-par - hell there are plenty of normally aspirated engines that can almost match that figure (Honda VTec, Clio 182, 206 GTi180, Toyota VVT, etc. etc.)