Different front and rear track

[MikeB]

the change in track width will just change the load transfer between the front and rear axle. If I remember right a wider track would give more load transfer on that axle.
So in theory you'll just need to adjust front rear spring rates to get the balance right again.
(lowering rear spring rate or increasing the front spring rate would bring the balance back for a wider rear track, think i have that the right way round)