This isnt twin or compound charging, this is a sequential turbo setup, been done loads, just not often on aftermaket applications.

IMO youd be better off twin charging it with a turbo and a supercharger, cheaper and simpler if you know how, and more effective too.

Or compound charge it like Dumped's saff with turbo blowing into turbo.

But all 3 ways are v.v.cool.

Love the way theyve done away with the intercooler by just injecting the nitrous into the compressor outlet too