Hi, I've been building hybrids for a while now. I can certainly help you build a hydrid, Are you to build one from scratch ?
Basically it's a little more tricky on a k03. You need a k03 turbine housing, k03 compressor housing. K04 compressor housing and k04 core, either a new one or 2nd hand.
The turbine housing needs to machined to accept the k04 turbine, once done the exist k04 fits directly in. Then you need to cut and weld the k03 and k04 compressor housing to mate the outlet of the k03 to the scroll of the k04.
I would suggest an uprated actuator as the stock one won't hold the wastegate closed at RPM
Balancing is only need if new parts are used.
I can supply all parts, balancing , machining, welding basically what ever you need to build one.
If running on an agu you'll need 346cc Saab red top injectors. S3/TT maf. Fmic . 3"dp and cat. Remap to 265bhp as a realistic figure, possibly higher.