Without going into too much detail, let's just say that the Pro-Design Cool Head's combustion chamber design could be improved upon GREATLY. The do offer increased cooling and looks.
Having the proper combustion chamber deisgn and parameters can increase performance immensely!! The only way to get the correct chamber design is to have the measurements (deck height, bore, crown drop, target RPMs etc. etc.) of the engine being modified. The combustion process is very complicated and often overlooked. A 70% squish area ratio is WAY much and robs power due to excessive trapped end gases and excessive turbulence.
Kelsey