Wheel Spacer Question

[tahoe97]

I was wondering about the wheel spacers i see for the 400ex.. are they for front and back or just one.. also are there any drawbacks to having them like do they put more pressure on parts and stuff..

I am 210 pounds and do some pretty rough riding and some jumping.. nothing too bad though

also does anyone have any pics of a 400ex with them on so i can see what they look like


thanks