Sport Springs on OEM Shocks?

Hello, is it possible to install a set of Sportline springs with the original dampers (shock absorbers) that came with an A6 from 1999?

Nothing is impossible.
However, only what is stated in the expert's report, specifically the section on the suspension components, is permissible according to the German Road Traffic Regulations (StVZO). This includes information on vehicle compatibility, installation requirements, etc. The dealer is obligated to provide this report.
It may be permissible to install these with series dampeners, but it is not mandatory.
It is practically impossible for feathers to be loose when fully extended and potentially change their "position."
A conformity inspection according to §19(3) is usually required. If no expert opinion is available, a separate inspection by aaS (TÜV) according to §21 is necessary.

Hi,

Sure, that's possible. Find the right springs for your car, and then you can do it. However, it doesn't really offer great comfort, because the original shock absorbers aren't perfectly matched to the lower springs – that's logical. I've also used Bilstein shock absorbers with H&R springs in my A6. The shock absorbers will wear out a bit faster if they're used with lowering springs, so you should get shock absorbers from Bilstein or similar brands that are designed for slightly shorter springs.

Regards,
arne