Yes and other customizable things such as separate two stroke and four stroke engines and different exhausts that can change sound depending on if you want a sporty sound or not. And added backfire if exhaust is very short.

And radiators and air filters that you have to hook up. And diesel engines in future

Regarding diesel and gasoline engines.
I might be wrong, but i think the main differences are (this is without going too deep into technical details):
* sound (pitch)
* max rpm
* rpm at which angine genetares max torque (power bank)

These 3 options are already aveilable for us to adjust meaning that we can already make engines that theoreticaly are similar to either gasoline or diesel.