What is the best way to remedy this? Stiffer Sway bar, thus less body roll? Spacers (what size)? Other fixes?
Under what conditions does it rub? When both wheels go up, or during cornering? What do they rub on? The wheel well liners, or the strut, or the fender lip?
I would be VERY hesitant to try to fix a rubbing problem by changing a sway bar. Sway bars are for changing cornering balance, not for keeping aftermarket components from fighting over real estate.
My snow tires (215-55-16 on E1 wheels) rubbed the back of the wheel liner, just in front of the muffler, because the rolling radius was larger than stock. That was easy to fix - I just cut the liner with a tin snips.
-Kurt