I didn't get that out of bernard but I would think it should have the latest piston which is a completely milled piston with a dome design and turbo top (circular indentation) instead of flat .

Bernard and I discussed the differences between the two pistons (all milled and cast then milled) and both thought the new pistons will be more resistant to breakage/defects but also will be heavier .

The guy who won open ( team losi driver mike (or kevin) gahan, team losi driver and management, shouldn't have been in open ) was using one . The engine was good , nothing special but good .