So...if you want to do the same thing, you need a few extra OEM parts....specifically;
8 - Screws (01451-00841) six of these hold the center mesh-like trim piece in place, and two hole the black exhaust surrounds in place
4 -Plastic Removable Rivets (N5042-5DA2A) two of these are used at the corners near the wheel wells, and two the connect the bumper panel to the exhaust sub-frame pieces
Also, you have to remove the rear tail lights (body mounted halves) and the bumper cover. You can NOT add the sport parts with the bumper in-place. This means you have to half-remove the rear fender flare trim pieces (this was a pain in the tail and I snapped/broke one clip on each side.
I cleaned the exhaust tips with steel wool and acetone, and painted them with 500 degrees caliper paint...but the paint did not stick very wheel...it had an orange-peel finish. I just needed them to be mostly black as I bought some metal "splitter" covers that apply to the surface. But if you are trying this, and want black tips, you may want to buy and OEM set.
There is also a large shaped piece of black rigid foam (can be seen in the photos below) which is installed with double sided tape in the main bumper that must be removed and discarded, and was as two 2"x 1/2" felt strips on the bottom that cover a hole you need to utilize.
Well I'm trying to add more photos, but something is strange. Each photo uploads and then disappears....anyone know why this is?