Parts are already made for these cars by English companies.I'm emphatically against the creation of replicas when it involves the destruction of an original car to obtain the drivetrain. It appears the Pur Sang cars are built completely from scratch. In other words, no vintage Alfas were harmed in their creation. I would, however, exclude them from vintage racing and concours events unless it's for display only.
One side benefit of Pur Sang's work is that their recreation of parts for the 8c may be able to supply unobtainium parts to get original Alfas back on the road.