I am thinking about to fit 20x8.5 in the front and 20x9 or 10 on the back. Is there going to be any problem or things needed to change???

 

Think this has been covered before... vossen 20's come in 20x9 and 10.5... 19's come in 8.5 and 10 i beleive....

I'm not a fan of staggered on FWD or AWD, i'd go 20x9 all around or 10.5 all around if you want to do alot of roll/pull and suspension tinkering for that super concave look...