springs and shocks on my A3 brought things into a line a tad. They lessened the body roll, stiffened up the ride, and the wheels tracked much better so as a result, you got less understeer powering out of bends.
Basicly, they made a BAD handling car reasonable.
Eibach anti roll bars made it feel like a TOTALLY different car. They totally changed the balance of the whole car, and completely altered the way it handles and drives.
Fitting the eibachs eliminated all the nasty body roll, and made the car totally neutral instead of its previous tendancy to understeer.
the traction now is incredible, even in the wet. Unless your silly and go full power before the apex of a bend, it simply will not understeer at all.
I'd say of the £3k I've spent on mods for the A3, the eibach ARB's were the single most worthwhile mod of the lot!