Keep or drop emission control?

Hello jagies !
My E-Type 73 American reimport was originally equipped with the emission control system (as you will know). On my second XJS engine (bought as spare and to learn) this was dropped and the holes in the inlet manifold were closed by welding. I have all the (expensive) parts required to reinstall a functional system again but you might recommend to get rid of it for performance (and optical) reasons ?
I was thinking of dropping the system but not welding the inlet manifolds but close the holes with small plates instead and just keep the parts (pump, filter, gulp valve, …) for a possible reinstall if one wishes.
Another question is why the vacuum pipes are attached to the right air filter but on the left side to the carburetor instead. I think this is true for both emi/non control.
Sorry if this topic has already been covered in other threads.

1973 engine?

Guarantee Emissions parts are no longer functional. That air pipe is clogged.
Remove and keep.

Are we talking about an air injection system and pump? Or something else, like perhaps an EGR system?

Air injection system and pump with filter yes. With all the modifications to the balance pipe, the air filter housings, intake manifolds, the special bolts on the exhaust, …

When I restored my 74’ 10 years ago, I removed all of the assorted emission controls…they basically only really worked on warm up anyway, right? The only vaccume line I have is to the brake servo. Have 40,000 miles on this setup and car runs great. Plus the engine compartment looks much, much cleaner and is easier to work on.

On a car with O2 sensors, yes. Earlier cars I think they ran all the time.