Art Loudspeakers, upgraded Crossover components

I just auditioned the Deco line of Loudspeakers from the Scottish company Art. They have an interesting take on an upgrade path, that I do'nt think I have seen elsewhere. Each speaker in the Deco and Emotion lines are available with basically the same cabinets and drivers, but 3 levels of crossover components. You can check the details on the website

http://www.loudspeaker-art.com/deco%208.html
I was pretty sceptical, but comparing the results, the differences are immediately clear, in terms of clarity and imaging in particular. Part of my scepticism is the cost. The cost nearly doubles between the cooking and the Signature version, with a comparable increase to the Silver Signature. I was partly reassured by the dealer, who explained the Deco 10 Silver Signature needs 20lbs of pure Silver wire for each speaker at a cost of about $28000, just part of the material cost. I have'nt heard the Silver Signature, but the change from the basic to Signature is obvious. In fact the dealer said with the 8, 10 and 20 versions, he sells the Signature at a minimum. The speakers can be upgraded at the cost difference in the purchase price, at any stage.
It really suprised me, how crossover component quality can make such an obvious difference. Is anyone aware of other companies offering a similar take on upgrading?