If the wires are in good shape then there should be nothing wrong with that gap.

On platinum plugs and autozone plug wires that 0.045" gap worked to 12psi for sure that I know of and nary a misfire.

I Never ran less than 0.040" with either my NGK TR6 and with my autolite double plats. The latter were in the car when I sold it.

You should search for a spark plug threads and ignition system threads from last year in this forum. I explained how you can't really take the plug/wire combo by themselves in your assessment.

Essentially you have the plug, wire, coil, coildriver (in pcm), and atmosphere in the cylinder that all affect the firing of the plug. THe atmosphere being fuel and air under anywhere from 10:1 to 16:1 compression.
The more boost you run the more that the air/fuel mix begins to act more like a solid insulator in between the plug electrodes (anode/cathode).

So two things can be done at that point: 1. raise the voltage or 2. decrease the resistance.
Raising the voltage is the best because the spark gets more energy this way. However it is less practical and costs lots of $ because everything from the coil drivers out has to be replaced.
Decrease resistance is as simple as changing plug wires, or sparkplug with different core, or shortening the plug gap. Remember, the plug gap is an insultor by itself and the wider the gap the more voltage required to push the gap. Therefore the wider the gap the more spark energy you get.
You would only reduce the gap if you are getting a misfire and stop as soon as the misfire goes away. You don't adjust the gap till you know your plugs and wires are good to go as this is the last and only user-adjustible portion of this after you choose your plugs and wires.
If you experienced misfiring at that tight of a gap already then you either have a plug wire/coil/plug problem, or a lean/rich misfire as you pointed out. Change the wires and if nothing changes then proceed back on course with fuel delivery.

Now, I'm not sure why your fuel psi is low. But fuel trims should tell the tale as long as you didn't turn off the pcms ability to learn.
If you have fuel trims showing that you are running lean, as in negative values on the long-term trims, then possibly the commanded A/F is too lean and the pcm is pulling fuel and thinks it is rich. Then it can misfire.
If you have fuel trims showing you are adding fuel or trying to run rich, then you need to add fuel.

You have the commanded A/F values that should have been left alone for the most part.
Then you have the fuel psi table, I'm not sure on this one.
Then there is the MAF function; this part must be right for the other two to work at all correctly.
Then you have timing which wouldn not likely affect the A/F but maybe the misfiring.
And injectors.
Of all these things the MAF function is most likely the culprit in my opinion.
I would think it is possible the pcm has altered the fuel psi down as low as it can to compensate for your car running too rich...or thinking that it is.

You must have a valid MAF for these things to work.
If you don't know if the MAF function is entered correctly, then you can put your stock MAF on and not run any boost past 3-4psi until you get the problems worked out.

Just FYI, I was able to leave the turbo in place but not hooked up in the garage while I installed the factory intake laying on top and ran factory injectors with the stock code.

For testing purposes it validates everything else in the system for engine operation like fuel, vacuum leaks, oil leaks, etc and takes the turbo out of the equation. I was able to cruise around the block too...sounded kind of weird with the air woosh though.

Anyway, sorry for the long post.

Former owner of '99 CSVT - Silver #222/2760 356/334 wHP/TQ at 10psi on pump gas! See My Mods '05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red '06 Mazda5 Touring, 5spd,MTX, Black