I could really use some advice on switching to 35s

I've got a 98 Sport 4x2 with a 3.27 open rear end. I'd like to trade in my 31s and get some 35s. Since I've got a 4x2, I never really get to play in the dirt.
So can I still get these? How badly will it hurt the Ex's performance? I get 20 mpg in mostly city driving right now.....
Thanks in advance,
Karl

 

[slravene]

what size tire are you wanting to run?