I'm thinking about putting HELOs' HE866 22" wheels on my 2013 Grand Cherokee, can anyone tell me if they will effect the performance and handeling on my Jeep.
Yes, you are changing the unsprung weight and total sidewall thickness, so the performance and handling will be affected. Better or worse is a matter of opinion.
From a looks perspective...I would go with the 22s. Due to the lip and spoke design, 20s will look small on the WK2. You will definitely have a firmer ride as you'll be on a lower profile tire with the 22s. But if it will never see any unpaved roads, 22s will be just fine.