What happens with discoloring of the paint is, the metallic flakes in your paint begin to dull (because metallic flakes are what reflect the most light so they get the hottest in UV). Evenly (without the bra), this is unnoticable, since there is equal dulling all the way around. With the bra, you will see an even line in the paint discoloring where the paint is covered by the bra vs where it is not. I have yet to see a VX stock color with metallic in it, so dulling will be less likely to appear anytime soon.

Most discoloring does not occur because of rain. It occurs from UV. The paint bakes in the sun, and if the bra is covering the paint, that particular area will not bake evenly with the rest of the hood. I used to have a bra for my old Rodeo. I only used it for long road trips. Out of about 10 road trips (all in the sun), I actually could begin to see a line where the bra covered the hood, comapred to where it did not. And waxing is a myth when it comes to this. Paint still bakes, heat is heat. My Rodeo never went 2 weeks without being waxed and machine buffed. I am not saying you are getting "0" protection from wax und the sun. I am saying, the best protection from UV rays for paint, is staying in the shade. Unfortunately, this is what the bra does.... adds shade to that area of your hood.

As for the bra fading and aging, never put any silicones or conditioners on it. Simply wash with soap and wipe dry. Getting it wet will not damage it, but letting it sun dry when wet will over time.

Just be more concerned with the effects the bra could have on your paint, and not the bra itself. The bra is cheaper to replace than the paint.