Definitely worth the upgrade from the basic manual gear shift knob to the R or GTi version whatever the cost - they are in my opinion like so many aspects of the RCZ (eg: the positive air vents on the rear parcel shelf) are a design triumph.
It's worth noting they're not chrome but a single carved billet of medical grade aluminium - yes medical grade! - and they're heavy - very heavy for their size - have a look at one carefully - really look at it - it's a stunning as a Henry Moore sculpture and a genuine work of art. And it's sitting there right under your hand every moment you drive it. Who needs to go to an art gallery - we have a modern masterpiece in our garages! I think they're the perfect complement to any well kept RCZ.
And if you want to keep them cool on a hot summer's day .... and we have plenty of those here in Aus!! - then a simple golf club head cover does the trick!