OEM is rubber, so will absorb more vibration etc and be more 'comfortable'.
Aftermarket is usually nolathane/polyurethane, so will be stiffer and more precise, but result in more vibration/noise.

It's really a case of what you want to achieve and how far you want to go with it.

Shifter bushings are a good start. There are a few different bushings involved, so again, it depends on how far you want to go with it.

Here's a pic with the different components of the shifter...


Engine mounts and gearbox mounts are also good to renew.


But all things considered.... Best way to approach this kind of thing is just to replace/upgrade things as they need replacing. If you go searching for things to replace, your list will never end!