First off    to Marlin.

I'd just rock the IFS for now.  Get to know your rig first of all.  These trucks are very capable rigs in stock form.  And once you get to the point, that your wanting a little more, then start looking around and see what you want.  I've seen some guys do some incredible stuff with IFS.  Just get used to tripoding out on the trail.  Cause, your always gonna lift a tire, when a SAS'd rig would go farther before lifting a tire off the ground.

And on a budget?  So, am I!!  I've been scouring the ads, and local forums for years, and when something comes along, and you got the cash.  Jump on it!!
I've gotten some pretty sweet deals from many members on this forum right here.  And it doesn't hurt that most of them likes cheese too!!    Get your parts when you have money.  Say buy some crossmembers this spring, late summer get some spring hangars, around XMas put new springs on the wanted list, and birthday season, put in for a dual case adapter.  This is what I have been doing for the last 5 to 6 years.  I've gotten axles, hubs, headers, axle rebuild kits, twin sticks, clutch, and so on, when I had the money, and the ability to get the parts.  Try finding stuff local, when getting used.  Because alot of parts are heavy and bulky, and shipping will cost as much as the part your buying.  I go to Fresno maybe once a year, and I'll make arrangements with members who are selling stuff in the area, and meet them there.  That way I'm saving a ton in shipping, since I'm down visiting family anyway. 

And as for a cold air box.  Toyota's air box is basically a cold air box to begin with.  The AFM takes in cold air from behind the driver's side headlamp.  And puts it through the filter, past the flapper in the AFM, and then through the tube to the Throttle body.  You can do the AFM swap.  On Pirate4x4 there is directions on swapping the AFM and Battery locations.  So your basically putting your AFM box right onto your Throttle body intake.  And your battery goes where the AFM used to be located.   You can put one of those cone filter setups on your AFM intake directly and eliminate the box, but your then taking in hot air from your engine compartment.