The difference is like night and day, and that's an understatement!!
I experimented by running no rear arb versus 16mm rear versus 22mm rear, the 22mm is head and shoulders above the 16mm, car just sits so much flatter, and is soooo much more stable at high speed on bends etc, esp when there are bumps, add to this a poly diff mount and you'll wonder how you ever coped before.
For me I did it as people said, it can't be done it won't work, just need to re jiggle tyre pressures around to get the best front/rear.
tabetha