I tried a project similar.I tried a variety of ways to make a compound turbo with a k03 and a k27. its doable, but cincy makes a good point about the ett with the newer compressor wheels. but if i was to try this again, i would use the stock turbo and a medium to small supercharger. i would also Y the supercharger into the factory charge pipe right after the DV port , and feed the supercharger with a inlet right after the maf on the factory TIP. if you try and feed one to another, you will gain a sick low end, but you will choke it mid to upper rpm.

but anyways, i have a k27 if you want it, with some extra hardware to go along with it if you want to try that out for cheap., you may have better luck then me.

 

I'm no Audi expert by any means...but I have a 87 Audi Quattro cs5000, and I've also been looking into twincharging. also known as pro charging, combining a supercharger and turbo. Looking on the internet I found turbo supercharger kits for my car. So my answer would be go for it! Even if it doesn't end up being as fast as you hoped, it's still twin charge. My question is, can you have a twin charged system WITH compound turbos=]