I run a pretty significant offset (I think it was 37 mm) -- a big change from stock -- with the spacers.

My guess is there is no noticeable difference in track, or if there is it is minimal.

You are to the point with that car that 8 lbs matters. I'd spend the coin on the lightest wheels you can find, at least one set. I have two sets of Volks and two sets of much cheaper ProRace 2s. I can't tell a damn bit of difference when driving, but there is a 10 lb difference on the scales.