Would you recommend either an ECU remapping and dyno tune or both as well or not?

 

Yes, you will want to find a local tuner who had Nissan experience. The software is called UPREV Osiris. Give it a looksie.

 

Ok sweet, I will. And I've seen people using HKS exhaust with Berk HFC (high flow cats), i've seen ART pipes with X02 exhaust, i've seen topspeed exhaust with berk HFC, etc etc.
Anyways, what I'd like to know is which of these exhaust combos (or maybe some other combo) would combine best with the Vortech supercharger for the quickest 1/4 mile street pull

 

Please just read that thread I linked you to on my350z. You'll find answers to practically all the questions you're asking here.

 

Most car mods/aftermarket parts say off road use only or not intended for street use. If you choose to put them on it's up to you. Do a twin turbo 2 step and anti-lag and scare your neighbors lol