Bug deflectors are really nothing more than a bit of added flash for your ride. The only way that they'd really protect your vehicle is if they came out a foot from the sides and up about 4 feet from your hood.
q
_~
The one that Nissan distributes is easy to remove to wax under the small area it covers, and it has about an inch between the hood and the deflector for washing with plenty of space in between braces for the water to run out from under. It also attaches into the holes under the hood inbetween crumple indentations, so no drilling required.
**I replaced the screws that came with mine with TORX bolts so that the provided tool for the roof rack can be used for removing it.
If i was you id buy it from Ebay. You can get it for about 40-50 $$