There is no inherent performance difference between the P11 and P12 head. All the gain is in the thinner valve stems.........but why would on run thinner valve stems for a track day vehicle?? One upgraded to the larger stem VET, all the advantage is lost and no they are on par
P12 higher initial investment, but the CAS reading above 7500-8000 becomes an issue (as hanz has mentioned)
You can keep P12 cams. And valve cover. An single solenoid.
Meh, if you are changing up, it will be a wash. P12 is several hundred higher initial purchase, so again, it may all be a wash once you go into machine work, etc.
YMMV
