The problem I have with the 9 way adjustables like that is every time you change the settings, you change bump AND rebound. And how much does it change both of them? I don’t know.
If you can’t separate bump and rebound, and let’s say you only want to slow the shock down in rebound so you turn the knob whatever way it says to slow down extension. Now, you’ve also changed the bump setting. Did the chassis WANT a bump change too? Maybe. Maybe not.
And the opposite is true too. What if your too fast (too soft) on your bump and you want to slow it down? So...you turn the knob to slow the shock down in bump, but you also changed the rebound. Did the chassis want the rebound changed? Who knows.
I know lots of guys go fast with stuff like that, and SS springs and snubbers, but that doesn’t mean there isn’t room there to make the car quicker with a better shock. I’ve seen cars that were said to be the best they could be, get on the corner scales and get exposed for bound up suspension, misadjusted suspension and other stuff. Cleaning that stuff up made the car quicker, even though the customer though his chassis was finely tuned.
It’s the same with shocks. When you can seperate out the bump and rebound, especially when you can do it on all four corners, you can really clean up the chassis tuning and find some ET.