I have a few items I would like to take out of my engine bay but unsure what the item does. The item is a ballast resistor I notice that it connects to the alternator, horn, a devices that power the windshield mist

You could take out the windshield wiper fluid spray assy and the horn if desired (it does come in handy & might be required (safety equip) in some states). You would need to go w an alternate coil that runs on full 12V to delete a 2 terminal ballast. Actually a GM HEI module mounted on a plate of alum under the dist does wonders for cleanup as you elim the big bulky ECU and the miniscule GM one (the HEI) is hidden under the dist

I did this to my truck,but it has been striped of most everything thats not needed to run and is more for race than comfort with daily driveing

went from this...

to this...

after cutting all this out,I ran them behind the fender brace to hid most of the plugs not used and to clean up the looks under hood

even striped the dash harness down to nothing

i used the heater switch to run the fuel pump and ditched every thing else but wipers/gauges