how can i upgrade the engine of the challenge edition to that of the cosmo ??

 

if i understand the question correctly i believe in Greece you have a standard power(challenge) adn a hi power(cosmo). if this is correct than you cannot upgrade from challege to cosmo because the engine itself is different- only 4 induction ports instead of 6 with different intake tract and computer programming.

 

you are right about the editions. but again are these 4 induction ports part of the engine or can be replaces,together with the ecu ? if not then there in then only the way of tunning the existing engine

 

tcannot change the induction ports. only thru tuning or adding forced induction(turbocharger or supercharger).

 

My dear friend, if u do not know, the Hellenic RX8 Club is running a long time now.

http://www.rx8club.gr

Come and join us, if u like.