I recently installed a new set of wheels in my '04 s2k.
I had a hard time finding wheels that I liked with the s2k factory offsets.
The new front wheels have a + 40 offset and the car now seems to wander a little during highway driving.
It takes more effory to keep it in the lane.\
Anyone know how this problem can be solved?

 

Alignment and maybe better/different tires.

Offset has exactly zero to do with the behavior you describe.