I'm trying to get my stock HU out and the first part of the removal is a PITA! The instructions from Metra say to:

Unlock the collar bellow shifter **** by turning collar counter clockwise and slide collar down. Using a small screwdriver or hook tool remove the spring clip to release and remove the shifter ****. (Figure A).

My collar won't turn at all.

 

You have to really use some muscle to turn that thing. Move the shifter down a few notches and try again. Use two hands if you can

 

do NOT twist the trim. just pull it straight down and it'll come off.

 

What he said. Twist and it could break.