Lighter wheels = Rougher ride?

[fredgroves]

You say OP that its 10% worse... would that be roughly the difference in the weight of the wheels+tyres you swapped out?

The dampers are "tuned" for a (range of) weights of wheel on the corner and the resulting forces.... and you've changed it quite a bit. Changing it a little you might not notice much (eg different tyres or swapping OEM 19's for 18's)

[MinchCS]

You say OP that its 10% worse... would that be roughly the difference in the weight of the wheels+tyres you swapped out?

The dampers are "tuned" for a (range of) weights of wheel on the corner and the resulting forces.... and you've changed it quite a bit. Changing it a little you might not notice much (eg different tyres or swapping OEM 19's for 18's)

The 18' Belvederes on the ED 40 (with same DCC) are even lighter than the OP's set up though so well within DCC factory parameters.

[fredgroves]

Same DCC though on an ED40?

Exactly the same dynamic shock part numbers?

[MinchCS]

Front dampers yes. Share same number.
Rear ED damper part number has now been superseded (twice) but I think they are the same parts too.
And you could order belvederes on normal GTi too.
The software might be different though.