Originally posted by strangerq
Specifically regarding the EJ207 shortblock having cast, not forged pistons:
MY03 EJ207 STi Piston Set -- $1022
This latest STi piston is a departure from previous years in that it is a cast aluminum design. However, we believe this to be a special hypereutectic material and STi claims a 120% increase in strength over their previous forged pistons. The high silicon content of the aluminum also has the benefit of providing exceptional scuff resistance and reduced thermal expansion which allows for the use of tighter clearances. Compression 8.0:1.
I also respectfully question the comments regarding the reasons for the price of the US vs. International (UK?). STI. The UK STI makes 265 hp and doesn't even have DCCD standard. Why would it be more expensive to make? It's notoriously difficult to compare msrp's in different countries.
Its cost, thats all there is to it. It is cheeper to cast a piston then to make one threw the forging processes. The uk and international are useing the older ver7 style set ups still. For some reason subaru stuck it too the euro guys this time. And again the jdm ver8 sti uses the hypereutectic pistions.
As trusted as rallispec is here they are still....
a North American component reseller.
Not an offical source.
Forged is stronger, and louder; cold forged piston slap may have had a little to do with the swich, but cost would be the more likely reason.