Are you planning to use the factory foglights or aftermarket lights? If you are going with aftermarket lights, you don't need the harness. You can tap the factory relay under the fuse box to turn on your lights. Look for the purple wire under the #39 relay in the fuse box next to the battery. I'm assuming you want to use the factory switch.
I hooked up a set of PIAA lights using the factory foglight brackets. Easiest way to mount them is to raise your headlights and remove the bezel. This should give you enough room to reach in and mount the lights. If you are still having problems reaching the area, you can unbolt the radiators shroud under the front fascia and reach in to mount the foglights.