i know the tc has iridium spark plugs already, i believe with a .7mm tip. can we see some improvement as far as performance wise the denso iridium power plugs with .4mm tip?

 

Personally I prefer NGK Iridium IX plugs

 

arent they pretty much the same? and can i expect any gains of any kind?

 

They are basically the same yes, Denso is just overpriced OEM stuff and NGK is less in price but the same in quality. You cant go wrong with NGK iridium plugs, when I switched over to them there was no difference in performance whatsoever.