They have everything to do with harmonics and resonance. It is possible to dramatically change the powerband on an engine by tuning both intake and exhaust. However, in the case of the ISx50, the resonators are primarily for sound reduction, not performance gains. There's plenty of empirical evidence from people who have removed them that they are not being used to add performance.

 

I see. Thank you.

 

It makes sense that at this level of machinery it is very difficult to gain performance without negatively affecting reliability and/or the environment when making modification. Otherwise the team of highly paid Lexus engineers would of already implemented it from the getgo.

 

That isn't always the case. Lexus engineers compromise performance on lots of things in favor of a soft and quiet ride (ie. not just enviroment and reliability).

 

^^ and government regulations. Any number of aftermarket parts ignore the emissions and sound requirements the OEM engineers had to meet.