I have perhaps more than one issue; not sure yet. Some background: I had my FD in the shop for literally 6 years with a guy who basically replaced.. everything. The car has a new wiring harness, all new vacuum lines, new solenoids, switches, boost controller, turbos, radiator, motor mounts, suspension bushings, oil pan.. lots and lots of new parts. Not a spot of rust or corrosion or even road grime anywhere on the car. Looks beautiful, but the guy was dragging and dragging on finishing it and said he wouldn't be able to, so I picked it up and took it to the shop that my friend and I have (we're decent mechanics, but this is the first FD we've worked on). I've owned this car since 1999 but haven't wrenched on it much myself in those years. Mods:

1. rebuilt 13B about 20 years ago, has ~45,000 miles on it, professionally done with upgraded seals (and it doesn't leak oil)
2. APEXi PowerFC w/ power commander unit
3. HKS EVC6 boost controller
4. GReddy intercooler and cold air intake
5. Racing beat full exhaust
6. downpipes/midpipes
7. New injectors: 550cc primary, 1660cc secondary, as recommended by BNR
8. Upgraded fuel rails & mark4 Supra fuel pump
9. APEXi coilovers
10. 18" RPF1
11. Koyo aluminum radiator
12. wideband AF gauge, boost gauge, oil temp gauge (A pillar)

so, as I said, new vac lines, new wiring harness. Mechanic gave me the car back needing some re-assembly, ie, the radiator had to be installed and the intake/coolant piping reconnected.. which we did, everything's together. Go to start the car - fires right up, awesome! Then I notice it can't idle to save its life, the wideband AF is pegged at full rich, and it's blowing unburned fuel out the exhaust pretty excessively. Giving it significant throttle floods it out and it stalls.
Checked the powerfc, still had the stock 550/850 injector sizes, so I upped that to 550/1500 (handheld won't go above 1500 it seems?) - no change in behavior. In addition, the turbo precontrol solenoid clicks rapidly when the key is on (but not when the car is running), so I'm not sure if that's an issue - disconnecting it doesn't fix the idle, however.

I'm not even sure where to start. I need to get this thing professionally dyno tuned, which I will do, but I want to get it running at least well enough to drive it up onto my flatbed trailer, and right now, that isn't possible. Any ideas on stuff to check? PowerFC sensor/switch page doesn't show any faults, if that helps.