I dont think it matters, the spark plug wires run directly against the 2 aluminum valve covers on all the 2JZGE engines, and under the aluminum throttle body. The cover thus makes no diff :-) PLus its actually about 2 inches above the valve covers, so it has no impact on all that stuff.

Our older gen GS's engine cover design is flawed, the back end of the engine, exactly where water from rain, road spray, and cleaning (dealers/car detailers/engine degreasing) is a water-trap, no where for the water to go, and its completely left open...They fixed it on newer gens with the engine cover front to rear. And then the problem doesnt exist on V6's.

 

My home-made rear-Engine Cover worked. We had some fierce rain and wind last night for 2 hours, checked the engine this mornig, and the water had dripped on the aluminum cover I made and back down the fire wall...the water drip is coming from a hole on the underside of the hood, in the dead-center a few inches from the back-edge of the hood...

Any way, here are the pics of the little cover I made which will no prevent water from getting into the spark plug area for good.