I've just gone back to standard offset on my 182 for et36 i.e and extra 9mm track each side.
The extra offset gave me some rather unpleasant handling characteristics that no number of visits to varying garages to get my geometry checked / altered could fix, namely tramlining and torque steer.
A bit of research online pointed towards the change of scrub radius due the the wider track possibly being the cause.
Whilst a wider track looks good and does provide some handling benefits, possibly more lateral grip, it also appeared to effect my car negatively.
et20 is massive and even if you don't run into clearance issues, could spoil the driving enjoyment / make the car unpredictable.