I am familiarly intimate with that 'tucking under' sensation, but no sign of it inspite of tyre condition.
Since alignment, a full bore emergency stop, straightline, hands ON wheel, resulted in the wheel shimmying, but not enough to lose grip of the wheel or control of the car. Car pulled up dead straight. Also drove back via a route which involved a really good handling test. 2.5 miles of dips, crests, sweeping and tight blind bends

Google maps, Haslingbourne Lane, Petworth (junction with A285), to the A283 in Fittleworth (junction with Lower Street).
Follow it on Streetview for a proper idea of the road.
The car was barely driveable, but following the bush changes, it drove ok on way to WIM and now drives well.
These bushes are a compromise, and whilst not better than genuine GM ones, they aren't as compromising as they could be. Should put a couple of thousand miles or so on them this month, but thus far, no new tyre wear, and no scrubbing under (very) heavy braking, fast bends, and full lock low speed manoeuvring
