Yeh the supra is a Flat six not a V setup.. =)
As for a twin turbo setup on a 4 cylinder car... I believe you are wasting money on something that will not give you any extra power.. And yet you might lose power potential because you are using up more energy to spool up two turbos instead of one.

It would be possible to do something like this, but you have to consider the heat that TWO turbos will be creating.. also have you thought of were you could place both down pipes ?

I think someone has asked about this one sometime before..??!@?

Best/Safest bet for you is to go with a Hahn/Star kit !