Seems you have misunderstood the main point. I need the SPDIF Input.. as RCA connector / Coaxial.
Those Xonar D1/DX cards don't have it. D2 ones do have though. But they are way too expensive. And so are the Essence ones.
The Striker does have the input, but it's an internal 2-pin connector. Adapter cable would be around 10$/€ more.
But still it seems a bit too expensive. The Auzentech Prelude looks like the best solution, as it has both Coaxial and Optical in the same connector. And it has both In & Out. Price though is again too high...
So to clarify the things I need:
Coaxial (RCA) digital input
Low budjet price.