One reason why the Scandi is such an attractive defense is because it is so forcing. In other defences to 1.e4 (Sicilian, 1...e5 etc.) White has about a thousand ways to deviate the game into their pet line whilst not sacrificing objectivity (still equal). Against 1...d5 this isn't the case. The Scandinavian may be the only reputable opening where on white's 2nd move he only has 1 choice where he isn't immediately worse! - 2.exd5
2.e5 is bad because of 2...c5 (2...Bf5 and even 2...d4 both also give black an easy and equal game)
2.Nc3 is inferior because of 2...d4 3.Nce2 e5 4.Ng3 (other moves are worse) Be6 5.c3 a6! and white has hard work to do if he wants to equalise.
The Scandinavian is the perfect opening to force white to play the types of positions black wants and is familiar in.
the qd6 scandinavian is on the border of refutation. After the shirov idea, nc3 d4 nf3, ne5, f4! with the intention of early g4 in many lines. White gets a massive space advantage and the one advantage black has which is comfortable piece placement is denied to him as the queen bishop has no good square. Black ends up miserable. its like +1 and not even combative +1 but a dreadful shuffle your pieces and hopefully white makes an error to be in 0.5 territory bad.
Could you elaborate on the line? I'm actually really interested in learning the way to play against the Scandi