Opti...Need help Plz

HI, dumb question, What year did they replace the stock opti for the vented one. Also how difficult is it to replace for a beginning mechanic? Prolly asked a million times but help is appreciated.

Thanks

The vented opti started in 1995. There's more involved that just bolting on a vented opti if you own a 93/94. The opti is driven by a pin on the end of the cam shaft for 95 - 97. 93 - 94 have a spline in the center of the cam that drives the opti.