oh, okay, i get it. i've only had hands on with the OEM parts so unsure how
best to advise.
removing the whole assembly from the door is two part: 1) remove plastic
mirror cover, 2) reaching through mirror guts with long shank, remove two
screws - top one, then the one nearest the back of car, 3) fold mirror unit
against spring tension and carefully remove last screw nearest front of car.
i would like to think that aftermarket parts would be compliant with OEM
mirror cover, but that's just a guess.
www.tinyurl.com/dmp6ph
http://tinyurl.com/5vrvv4