For one, I'd have gone with the standard Bosch Platinums instead of the +2s, the Bosch +2s and +4s tend to only do well in engines designed for them, the standard version of the Bosch Platinum is an EXCELLENT choice for the 2.3 though, as is the NGK V-power spark plug.
If you're getting spark knock, you've got a few things to check:
1. Vacuum/emissions lines. If any of these are cracked, broken, or disconnected, they could be causing the engine to draw excess air or not collect all of the various vapors (oil and fuel vapors) that your engine is also supposed to burn as part of it's emissions system.
2. Ignition timing. This should be set to match the decal on your radiator support. If it's not there, try looking in a Haynes or Chilton's manual for the car.
3. Camshaft timing. Camshaft Timing is very important on the 2.3, being off by a single tooth can wreak havoc with the EFI engines. There is a sight-plug in the timing cover of the 2.3L engine, rotate the crankshaft so that the timing mark on the crank pulley points to Top-Dead-Center on the compression stroke of the #1 cylinder (easiest way is to pull all the plugs out of the head (mark the plug wires so you don't lose track of where they go.) and place your thumb over the hole on #1 while a buddy turns the crank with either a ratchet, breaker bar, or their hands on the crank pulley (2.3s tend to be pretty easy to do by hand with the plugs out) when you feel pressure against your thumb, you are on the compression stroke, have him keep turning it until TDC is lined up with the timing mark) once you've got the crank at TDC, look through the sight hole in your timing belt cover, you should see a tiny dimple in the camshaft pulley, that dimple should be lined up with the timing pointer within the cover (center line if yours has three lines) if not, you need to correct the positioning of the timing belt, either consult a service manual or have a mechanic fix the problem.)
4. Fuel System. You need to know if you're getting enough fuel, you'll need to check the fuel pressure at the fuel rail and check the fuel pump for adequate flow, either check with a Haynes or Chilton manual or have a mechanic do this, you'll need a special tool (fuel pressure gauge) to do this.
5. If after all that you still haven't found it? It's likely in the valvetrain. If you're mechanically inclined, go ahead and dig in, if not? Check with a mechanic.
__________________ 1976 Ford Mustang II Ghia: 302 with a 600cfm Edelbrock carb, Edelbrock Performer 289 intake, Dynomax Blackjack headers, 2.5" exhaust with Flowmaster Super 44s. RJS 11-gallon fuel cell, C4 tranny, chrome 16" pony wheels, fuzzy dice, brown vinyl half-top, and painted in the tackiest color ever (harvest gold, that's why I call it "The Goldenrod").
Also have a 2003 Dodge Ram (lightly modded daily driver/tow rig/office/dining room/home away from home/workshop... I call it "The Big Blue Dawg".) | 
1988 Mustang engine knock even after mods. What to try next? 
