Best is not always the same as most valuable. The CSX aluminum Shelby's are the most valuable and typically upper tier quality cars. The Kirkhams are often an equal quality car but the absence of the Shelby CSX mumber reduces their value. Generally the most expensive Kirkhams approach $120,000, which is the starting price of the least expensive Shelby Aluminum CSX cars which are generally worth $140,000+. If you were buying a used Cobra (check out Cobra Country), and didn't want to spend more than $120,000, chances are you could find a better car (although probably not a better investment) in a Kirkham than a Shelby CSX Alum car. Fiberglass replicas start around 20,000 and generally top out in the 60,000's except for the Shelby CSX fiberglass cars which will reach or exceed 100,000. IMO the best fiberglass cars are made by Shelby, Superformance and ERA.