Steel subframes do not shift. The benefits you feel are from a fresh alignment and lighter wallet. Aluminum subframes can shift and an aftermarket deadset kit will stop clunking.
Here is the OEM solution to stop the aluminum subframes from shifting...
Sound deadening the hatch floor and wheel wells made a worthwhile difference on my GTI. I paired Noico 80mil foam with their rubber butyl to cut vibration.
RSE05 is my wheel for both road and track. Road comfort is a key reason since the only rubber left in my suspension are the tires and rear shock mounts.
On track I run 17 inch for tire cost knowing a 18 inch tire will handle sharper but extra side wall let's the tire communicate a little more...