96 HDJ81 HDFT car runs smooth when cold shutters between 1800 and 2000 rpm when warm.

[mudgudgeon]

I don’t want to mess with the engine at all. I just want it to run smoothly. It has enough power for my needs

Leave the exhaust as it is then.

If you want a bit more power, 3" exhaust and a tweak of the turbo wastegate and fuel pump can improve performance.
It can also lower EGTs and improve efficiency, which helps it last longer.

 

[80SeriesNomads]

Leave the exhaust as it is then.

If you want a bit more power, 3" exhaust and a tweak of the turbo wastegate and fuel pump can improve performance.
It can also lower EGTs and improve efficiency, which helps it last longer.

Great advice, thanks a lot. I've saved it, and when the time comes to make changes, that's what I'll refer to.