GT-S engine explanation

[ismatari]

Hi there hoping someone can do some explaining for me.
I have a 2006 GT-S.
I know that the GT-S has minor engine tweaks throughout its life particularly involving the max rpm limits. My engine bounces at 8200rpm.

Are their any other differences in the engines year on year?
The reason I ask is im intending to put on a Injen CAI however all of the websites that sell them only confirm they fit the 2000-2003 models? But what actually is the difference?

Can anyone help me out on his one?
And even if it doesn't help with my CAI mission it would be interesting to know what physical differences there are in the engine bay year on year

[Cali90sGTS]

never owned any other celica besides my 5th gen but the difference in those years of intakes i assume is the way the piping gets to the cold air and maybe your map sensor.. your newer models engine bay must be arranged a lil more different..