He bumper is made of polypropylene and absolutely fit like a glove.
Here are the parts that are required for a hassle free install.
51718040101- left fender liner
51718040102 - right fender liner
51758040111 - underbonnet (belly pan)
I bought all these parts from ECS Tuning and the belly pan came with the adaptor already attached.
The lip fit really good as well, I'll take some pics later today and post them up.
I love the new look and don't regret pulling the trigger at all.