So just how does the plumbing work on a set of twins? Like this? Exhaust manifold to small turbo , than onto the large turbo. Airfilter air to large turbo which than feeds pressurized air to the smaller turbo? Is the big turbo called the primary and the smaller the secondary? Just trying to figure out the plumbing sequence. I like fabricating and welding and think this would be an entirely doable project. Even more doable if you can use the stock charger with a "new" larger charger. Even better if the larger one is a commonly available unit that isn't really expensive.
Alan

 

You've got a pretty good idea of how it works. The stock charger will work, but will be limiting because if it's size. The most common primarys are ht3b and s400. Both can be found for a decent price if you look.

 

Here are some very sweet sets.

Scroll down a bit.

Jim