I hope you take reply correctly and no offense intended ...
If you're asking this question and don't thoroughly understand the systems that control the engine functions - whether they effect 'smog' or not - yore doomed to just end up with terrible running/driving non-smog vehicle
Almost any post-90s vehicle has electronic control of most timing, AFR and other operational systems for engine performance.
These post A.I.R./smog-pump engine designs use engineered combustion controls vs. added crud you could just unbolt and throw away.
There really is no valid reason to remove modern OEM 'smog' parts to improve performance unless you can program around that device and improve combustion efficiency.
Removal of a given part will most likely effect other systems, failure to engineer around this just destroys the operation of the engine.
Reducing intake restriction and improving exhaust flow can be positive efficiency and performance upgrades.
Anything beyond that requires a well thought out and engineered plan.
We can always address specific questions if you have them about any of the given systems and parts.
As always JMHO