I want to mount my Greddy Type-RS BOV just before my Greddy Elbow.

I'm running the stock twins with Greddy SMIC and piping kit.

What do I do about the stock ABV and CRV?

 

Why do you feel that you need to mount an aftermarket BOV?

 

Because I like them.

 

You're aware that you get the same sound by simply venting your stock BOV to the atmosphere, right? and that installing an aftermarket BOV will provide no real benefit while in the stock configuration.

Either way, I'd say you could eliminate the stock BOV if you install an aftermarket one, just put a filter over where the air from the BOV would recirculate into the intake, and plug/weld the nipple that would have connected the BOV to the y-pipe. Leave the rest.