I've now done about 3000kms with the RGS grill protectors so thought I'd post my review.
Firstly, I considered the Zunsport Grills but I didn't like the way they sit in front of the edge of the openings. Although I think Zunsport are slightly easier to install but don't look OEM, they look like an after thought but do the job fine. I think they also cost a little more.
I originally made my own out of flexible automotive diamond pattern grill which I purchased off ebay. They worked well but I wasn't happy with the grill opening size and they let some small objects through.
I shared my templates with Eric at RGS and bought the RGS ones at a discount price. You can buy them here: www.radiatorgrillstore.com
I think the weave in the RGS grills is perfect and very OEM. Doesn't let much through, even catches small feathers and insects but still provides adequate ventilation for cooling. Eric also lines the edges with a rubber coating so the cut grill does not scratch your paint. Although I'd still recommend a bit of masking tape in case things get rough with the install.
Install of the side grills is relatively easy but does require a bit of skill to slide it through the gap. They slide securely into some upper slots in the openings and have a couple of discrete cable ties at the bottom. I used two hooks (see photos) to manipulate them into place as obviously you can't get your hand behind the grill!
Installing the center grill is more tricky. If you are not mechanically minded at all then best leave this for your mechanic. Essentially, the center grill is larger than the opening so you need to make it into a concave shape then slide one side into the side slot first and then work the other edges into the upper slot and then the other side slot. Then pull the concave out with the hooks.
The center grill also has a fold at the bottom such that with the hooks you pull the fold into the sleeve at the opening. Eric puts some extra rubber gripper on the fold so it grips into the slot and doesn't slide back out. I did find it slid out a little after a while but that was after some pretty brutal driving and many hundreds of miles, but it only takes a few minutes to pull it back into place with the hooks and it still functions as intended regardless.
Overall, install is not difficult and I'm sure Eric provides good instructions! Note you don't have to remove the bumper for the install but I had it off for other reasons.
All in all a great system and advantage is that it looks very OEM and functions as intended. I wouldn't bother making your own! You can also still release the cable ties or the center grill to clean your radiators if required.
Here are my photos. You can see they fit perfectly flush behind the openings and not in front!
Wire hook tools (you will need at least 2):
On the road: