No change to the shock is necessary. Even with the completely stock shock the improvements will be very noticeable.
We recommend air shocks with this link. A coil shock can work but will require a very firm spring to keep from bottoming out because of the short shock stroke. An air shock is recommended because the end-of-stroke ramp can help prevent harsh bottom outs. If you already have something installed on your bike and don’t feel like replacing it there certainly isn’t any reason to.
This link delivers substantially more bottom out resistance than the stock link. Using 30 to 35% sag should be your starting point. If you feel you need a little more first try adding a few clicks of damping to account for the change in leverage curve. If you still want even more you can try going up 10-20 psi in air shock pressure.
At 30% sag this link will also deliver much better small bump sensitivity so start there. If you still feel like you’d like a little more try running less damping. The link makes it so the suspension doesn’t rely on damping as much to avoid bottom outs so running less isn’t an issue.
The link puts the bottom bracket and bike's geometry in the middle of the High and Low settings of the stock link.
Your best bet is to give Santa Cruz a call and ask them directly. Only they can make that decision.
Long travel or short travel. Which is which?