OK, answered my own question....shifter knobs are easy as per below. Insert is from our host, just in the process of getting ready to cover it in lambskin, but it looks OK just printed in ABS (100% infill and 5 outer layers for strength).
It bolts in using the standard method single 8mm. Turns out you can adjust the height of the ball a bit internally, I made mine a few cm shorter as I have arms like a monkey.
I tried 3 or 4 until I got the diameter and shape the way I wanted it, and I like the spherical shifter....but almost any shape is possible.
Here is the latest update on the console. It includes Autoheat/AC controls, alarm button, antenna up/down, PCCM box with dual USB as well as a 7 light warning system for low washer fluid, parking brake, oil cooler fan on etc.
I put in the orange lettering just for fun. Easy to do in Fusion 360, just do the text (Porsche font in available online) in a sketch, cut it all the way through the object you want the print on and then do another extrude to make the letters in a different colour. I put a 0.25mm backing plate on the letters which seemed to help them print on the Bambu.
Then snap the letters in, tap them into the object - plenty of friction to hold them in place.
the "dot" on the 3.4 was a pain as well as the inside of the "9".
Other than that....looks ok and everything works.
Just get the knob covered in leather and it will be perfect...
D.