Strange that a £100 reconditioned MGB rack is used as an argument to keep the cost down in a £300 000 pluss car.
They are new racks, not recon. All of the SPF cars that are vintage racing in the US have the MG rack. The Cam Gears rack is a couple of thousand pounds I am told. Again, you can bolt on in as the original mounting points are on the chassis; there are backets that adapt the MG rack to the tub. If you need the magnesium rack, go for it. Hi Tech (the manufacturer in SA) also replaced the magnesium uprights with aluminum in the original FAV design; magnesium has a short half-life on the street with exposure to several things that degrade magnesium.