Should the SPD ask for changes or offsets to the Fiscal Compact or simply vote it down?

This is a follow up to my post: Who will raise the progressive flag in the European political battlefield? Hollande or SPD - Greens?

It is being reported that it is doing the former.
In my opinion, it should do the latter.
If the Fiscal Compact ratification fails in Germany then many other of the 25 will follow. And a proper Pact, not simply fiscal, can be negotiated.