Theuns, one thing about the BVM intakes is that they maintain an constant cross sectional area from inlet all the way to the Viofan(or if any reduction it is done very smoothly). I believe this was critical for the fan to operate optimally. The hard part is actually checking that due to the complexity of the inlet shapes being 2 approx. half circles being slightly oblong. You will probably want to smooth out any transitions to avoid any losses
Darren