The brief
The owner described a heavy thud from the front of the Touran every time it crossed a speed hump, a small shimmy through the steering when braking on uneven surfaces, and feathering on the inside edge of both front tyres. All the symptoms of the front-axle subframe not holding the geometry it should.
The front subframe is the cradle that carries the engine and the front suspension, and it bolts to the body through rubber bushings that locate it precisely. When those bushings collapse, the whole subframe can shift under load, and that movement is the thud over humps, the shimmy as the geometry wanders under braking, and the uneven tyre wear because the wheels aren't sitting at the angles they're set to.
The diagnosis
On the lift a pry-test confirmed it: the front subframe bushings had taken on visible deflection in both planes, with the rubber separating from the inner sleeve and cracked through. The other suspension components, the lower arms, the links, the engine mounts, were all within tolerance.
So the right call was the bushings, nothing else. Replace those and the whole front end is located properly again. A four-wheel alignment afterwards, since dropping the subframe moves everything.
The work
The engine was supported, the front subframe dropped out enough to reach the bush seats, and the failed bushings pressed out. Fresh VAG-spec bushings were pressed in to the correct depth, the subframe bolted back up with new bolts torqued to spec, and the car rolled onto the alignment rig for a four-wheel set-up.
A road test confirmed the thud was gone and the front tracked straight under braking.
The outcome
Clunk gone, shimmy gone, and the alignment back on spec, so the front tyres will wear evenly again.
The Touran went home tracking straight under braking and silent over speed humps. Subframe bushings carry the whole front end, and once they collapse the handling drifts and the tyres pay for it, so pressing in fresh ones and resetting the alignment put it all back where it belongs.