what year/model was variable valve timing introduced?

thanks
pete

 

From the bugeye in 2001 and then went dual avcs for the hatch

 

Bugeye Sti onward came with single variable valve timing (avcs), where as Bugeye jdm Sti onward came with dual avcs. Uk bugeye Wrx onward didn't come with avcs but jdm bugeye Wrx models onwards came with single avcs.

 

Bug JDM onwards also had single avcs.

As Banny said duel avcs was not introduced until the hatch I've got a JDM blob and that has single avcs.

 

I can imagine jdm wrx bugeye to hawkeye & uk & jdm bugeye sti to hawkeye all have pretty similar heads.