Other proceedural advise:
Decide on your turbo FIRST. This decision will affect your exhaust choices, intercooler choices, and ultimately how much power your setup will be capable of.
If you're going to go FFIM, decide on that, too, since it will likewise have some far reaching consequences, and you don't actually have the money to buy stuff more than once if you're going to go for good stuff. If you are going FFIM, your budget gets tight.
Driftmotion's intercooler kit is pretty generic, but I have their 2.5" Spearco replica, and I'm very happy with it. The 2.5" piping kit is totally generic, as in cut your own to fit. I want to do mine over again, since I have more couplers in the line than I really wanted, but it has enough parts to make stuff work. You may well want to get a shop to custom fab something for you.
So, turbo first. Then intake and exhaust plumbing. All this can be done running everything else stock so far (Though fuel cut won't be far off with stock electronics, even at stock boost levels.)
After this, and before cranking up the boost (Maybe start here, even) I'd toughen up the engine. Forged pistons and rods, metal head gasket, and some ARP hardware to hold things together. Really, you'll dump a couple of grand into this stage, but if you don't do it first, you'll pay the price later. Expect to lay out a couple grand on parts alone here. For me, I've got shot-peened stock rods, so I didn't buy the forged ones. My pistons (Arias forged) were about $700, another couple hundred on a Titan MHG, More on ARP head studs, plus new oil pump (Good insurance) new water pump, new timing belt. The bill from the machine shop would have been a bit over 2 grand if they weren't one of my clients and I scored a great deal. This is with the machine shop assembling NOTHING, though they did polish 2 cranks for me. Add in the oil filter relocation and full-flow oil cooler kit, and I'm probably $4k in with the bare block on the stand. That's with no turbo, (I already have an aftermarket 60-1) no exhaust, (I already have one that's 80mm turbo-back - LIPP elbow, RT downpipe, and Tanabe exhaust) no intercooler (Already had, plus HKS SSQV) and no electronics. Also, that doesn't include cost for the rods. Wouldn't be hard to put $5k into the block. Oh, mine DOES include a valve job, but NOT doing the shims for the cams.
So I get you at $5500-$6000 with a block built to make 500HP, and a turbo, intercooler and exhaust that can get you there, but not enough fuel, or engine management to get you past 300HP.
The cheapest way to 400 at this point is 550cc injectors and a Lexus AFM, with an AFPR and a fuel pump, which is about as far as you go with your budget, but later, you can get larger injectors and a stand-alone to get the rest of the way to your goal.
At 500, the 7M-GTE is very doable. For 600-800 or so, then your first step is probably to buy a 2JZ-GTE and start planning your swap, since it'll probably be cheaper than the 7M.
