Track S4 vs, A4

[rjkflyer]

Curious that the S4 has a narrower track than the A4 (saloon and avant are same in each range).

A4 F/R 1564/1551 mm
S4 F/R 1552/1539 mm

Almost looks like the track has been narrowed on the S4 to get wider tyres on, but obviously not the case as you seem to be able to get those on the A4 also.

So, unless the suspension is fundamentally different geometry (not usual for an 'S' vs. an 'A' although common for an 'RS') the wider wheels must have less offset to compensate?

Never spotted this before...