I'm not entirely sure what it is you're after - bigger air intake for 2 cars, one being a CFI and the other being an EL Falcon? Is that right?
Either way, this will probably be moved to the tech forums, so i'll keep my answer short - for the CFI, do the MPFI conversion first as it's just soooooooo much better (ask anyone on here who's done it), and without it, your air intake mod isnt going to make much of a noticable difference.
For the EL - I'd go a K&N/BMC panel filter in your airbox, AU or better still mandrel bent intake piping from airbox to throttle body, and a Tickford Snorkel. SS inductions is a complete waste of money (and a very big one at that) as it's basically just a bigger snorkel.