You have to crank the torsion bars to lift the front, there is no other way around it unless you redesign the front suspension (i.e. solid axle swap, etc). The 18's shouldn't change the stance unless you get the Borbet's, I think the 16" chrome wheel and the 18" chromee wheel have similar offsets (someone correct me if I'm wrong). I have 16's on my 99', it had the 18" Borbet's on it when I bought her. I used 16" Isuzu Snowflake wheels and they widened my stance a bit, I'm running OME 912 springs in the rear with no spacer and cranked torsion bars up front. Here are some before and after shots for you:

Before:




After: