You wanna sell up pipes?
Make divided up pipes that use an adaptor right at the turbo.
Same up pipes would be able to be used on T3 and T4 turbine housings...
You just include 2 adaptors with the kit, one adaptor is a true T4 divided spacer plate...the other is a T4 to T3 adaptor plate.
Both spacer plates would have to be the same thickness...this would ensure the uppipes could be used on every non Vgt turbo out there in a T3 and T4 size.
Also, keep the EGR v band connector...just include a block off plate, and an extra v band flange which would be used for a wastegate if required.
I call dibs on the patent pending though....
Either that, or partner up.