One of my friends noticed that the front of my car is unusually low. He went on to press downwards on the front of the car and try to move it up and down by pumping on it. Then he finally said that I'd have to change my shock absorbers. He's just recommending that I change the one at the right. How much do you think would a replacement of a shock absorber cost? And, should I just replace the right shock absorber? Or should I replace both the left and the right?