Are the splash guards for the wheels actually do anything for the performance/safety/protection of the vehicle or are they just something dealers can charge extra?

I like the look of the guards, but each winter I always get a big snow clump behind each wheel and the guard, and unless I kick them off I can see my wheels actually grinding against the snow buildup, which is annoying.

 

i guess they are to prevent mud from hitting your car by the tires.

you can take them off and sell them to me assuming they are off a 99-00 civic coupe

 

Performance, no. If anything it'll just decrease MPG's slightly due to more air resistance.
Safety, no. Unless you constantly get hit in the eyes by little pebbles...
Protection, yes. It does help keep dirt off behind the wheels and also any debris(rocks mainly). Makes cleaning a little easier since there won't be so much buildup behind the wheels dirtying up your towels when washing/waxing. Minimal but effective. Find some used ones, new from the dealer are mad expensive..

 

are they easily installed my a novice or should I go to a repairshop and ask for their help?

 

u can install them yourself, just 3 screws