If you wanted to fit an aftermarket one just go to a company like Richbrook, state the type of model car you have and they will then tell you what style you will need and how to overcome any problems fitting.
As for the the plastic bit underneath the gearknob Richbrook also can supply 'an upgrade' all alloy one.
The choice is yours bud.
There are so many on the market it really is what takes you fancy!
Macca