I thought that last election the slight non - PR aspect of the German system favoured the SPD since they managed sweeps in some of the new Laender with under fifty percent of the vote giving them overhang seats. Could well be different this time with the LP winning more direct mandates.

When you say a SPD-LP-Green coalition is impossible is that because of the numbers or due to resistance within the SPD and the Greens? I think that even if it got a slight majority it would still be impossible due to the strong hostility of many within the SPD and Greens to the LP and vice versa.