Are they NA pistons? or you running higher comp with low boost???
They look amazing quality. Yeah its hard to tell even cams having
this full black anodised looking coating but someone cluey dude
on performance forums explained how its done and although designed
a while back this DLC or VDC - basically a black diamond coating
along with other similar processes make more hp by improving the
thermal efficiency by keeping surfaces cooler and very slippery.

just in case you guys didnt know Lampy who once owned my old vb10
before I bought it back from him has had built the closest thing
to an LZ engine, an L18 with KA24DE head which Les Collins built
and now making 282 hp ate @ 9000rpm.
http://www.lescollinsracing.com/engine/projects-engine/l-series-4v
http://www.youtube.com/watch?v=TvePhfdrun4
heres another but 2.3L, 8hp more at lower rpm & 30lbs more torque
http://www.youtube.com/watch?v=LLOEO3xkN4c