I fear you've got that arse about tit, the SNP is (was) a political movement (none of this manifesto bullshit) to devolve powers from Westminster to Scotland and as such a vote for SNP as Alex Salmond has already suggested could put Scotland in a far stronger position should there be a hung parliament.
Scottish elections on the other hand should be about selecting the policies we want from our Government.
The SNP has lost it's fundamental purpose.
They'll still get my vote though, better than the champagne socialists in London.
I'd be very happy with a hung parliament, and with the SNP holding the balance of power. That would certainly be good for Scotland. Unfortunately, I just can't see the SNP winning anything like enough seats to achieve that. My fear is they will take a few seats from Labour, but only enough to let the tories win overall, and with a workable majority, which would be a nightmare scenario.