Check the wash/detailing forum for wax info.
I drove a 320is with a bra for many years. As far as protection it worked well and for the money, it's cheap. You have to remove it to open your hood (obviously) and also when washing the car. When left on for long periods junk can collect around the edges or just under the edge. Also, you have to be careful of the mounting method because whatever is used (mine had cloth covered bendable aluminum) can scratch the fender wells. If you aren't careful you will be rubbing out your paint on a regular basis.
On my current ride, I have the 3m film and Xpel film applied over mutliple locations (front/rear bumpers, full hood, back of mirrors, door sills, door cups, front lights, front/rear mud guards). If you search this forum you'll find I've posted many, many pictures of the installation process. Or click here<---. Or here<--- Or here<--- Or here<---.
It does protect the clear coat/paint from rocks/pebbles and you really can't see it unless I point it out to you. However, when it is dinged, there is no easy way to remove the blemish. The installer stated that he has done "micro-repairs" where a tiny bit of the material is cut out and replaced. One good thing is that these tiny blemishes are not readily visible unless I point them out to you and you are a few inches away from the car. Also, the less expensive front end kits contain multiple pieces that do not wrap around the edges of the bumper/hood leaving many areas exposed to micro-damage. I had the hood custom installed because I wanted it wrapped around the edges.
While it's removable, it's not necessarliy reusable. It's clear except for the edges that are not really visible from a few feet away. In addition, it will yellow over time. The Xpel is guaranteed not to ever yellow. You wash and wax it like regular clear coat/paint. If you drag something across it, it can be scratched and ruined (like what can happen to the top of the rear bumper.
Sometimes the edges can come up and when dirt gets under it, the entire piece has to be replaced. The installer should replace it for free as this is an installation problem.
BTW, where are you located. If in the L.A. area I can refer you to my installer.
A bumper/hood kit will cost around $200-$300, installed by a pro. To replace a piece is time/material cost. After watching the installation, I would not attempt this as a DIYer. Too many chances to screw it up.