Most engines are a compromise and it is only the ones that are live mapped that are getting the full potential of low or high comp / max ignition / high boost anyway.

As long as the car is live mapped, you shouldn't have a problem either way, as you take the engine to the point of det and then back it off, so it is swings and roundabouts.

Each engine has to be specced from scratch and EVERY single component matched to the spec to keep the cylinder pressures at an acceptable level.

The way I went about doing my engine was firstly deciding what power output I wanted to achieve, then I decided what turbo I was going to use (based on my power requirement and the optimum boost that this turbo was most efficient at). From there we were able to work out what was the highest c/r we could use to give accceptable cylinder pressures. It was then live mapped on an engine dyno with the maximum ignition advance the above could cope so that det occurred (and then backed off to a lower "safe" level) and obviously the fuelling matched to this.

The engine exceeded it's remit by almost 30bhp, so I was WELL happy and it feels like a T3/4 car down the bottom end . EXACTLY what I wanted - a good point and squirt car.

Most people are chasing numbers without ANY consideration to how the car will drive. I have an engine that is considerably less powerful than most T4 equipped cars, but I think it is much more driveable than almost any of them...