Is there an advantage having wheel spacers on the front as well as the back?
Is the rear good enough for extra stability?

im wondering the same thing

The only thing I can see with spacer are if you have wider tires that stock, some might rub the side of your ATV, that Why if you put 28" on P650 or 700, it's recomended to put spacers. It's will put your bike a little wider as well.

I've got no problem's with 27" on my P700 without spacer

That is another part that can run loose???

My 2 cents and I can be wrong...