For me it worked out fine, my FZR can upgrade from 140 to 150, but it created problems when people tried to put a 160 on it, because that would pinch the tire. Stability of the bike is much better, I've did some stupid things when turning the bike in slow speed, and it's been forgiving, so suffice to stability in both speed and coasting has improved dramatically. Rider's height changed, but not enough for me notice. It's eating up bumps pretty well, even though rear suspension on my bike sucks.
My advice is to do some research online as I did, other people who tried it before will tell which upgrade safer, and which is too much. Usually, one size up or down is ok. But it doesn't hurt to check.