There are 100's of things you need to do to some cars to stop them pitching, rolling bottoming out, or simply driving in a straight line. Set up/good maintenance is 90% and driver skill/style is 10% of having a car that behaves the way you want it too. An anti roll bar is not the be all and end all. Some shops will advise you have to buy things to cure a problem - Ask to see their race cars and see if they have them on.
If a car rolls when you give it a fist full of steering to get round the corner at the end of the straight.... If your car is set up ok and works well on the rest of the track then try batting towards the corner, chuck the anchors on few yards before, then roll round the corner before giving it a fist full when you're straighter.
At the end of the day I'm not for or against any car/spares manufacturer, shops or anyone else who may give advice. I have no problem with people putting what ever parts on the car they want to - it's their choice. When someone asks questions, I'll reply to them if I know the answer.