If you are fair and respect racing rules, I can't see any problem. After all this is racing, and overtaking IS and SHOULD be part of the fun. You might find a few fast guys that will unfairly bump you off, but bear in mind that these are not real racers, if you meet one of these just let them pass, after all they don't deserve your respect. But most love a good race.
You have to of course follow the racing rules plus a few common sense ones.
-leave space for the other car, if it's on one of your sides don't push it off the road.
-don't go blocking like mad. you are entittled to one blocking move, and a return to your racing line. As long as the other car is not already occupying that space (one or both will fly).
-If you loose control, and because of this loose speed or leave the track. You loose your rights. Don't go trying to fight in this case. Recompose yourself and remember the race isn't over.
-If you are passed, sometimes the passing car has to take a less ideal line which will allow you to re-pass. But remember, don't crash into him.
-A fight with another car will by definition slow you down, so if your direct fight is with another car, just let the other car pass, and get on with your race.
-Be in control of your car, learn when to go fast, you can't attempt to break your PB on every lap, you'll end up making a bad mistake.
-Enjoy your races, finish them. A last position is better than a DNF.