yeah J-Spec don't actually own any of the cars we list... they're sourced from dealers, wholesalers, agents, auctions etc. when a customer wants a car they pay the seller directly. Fairly sure that R35 was from a wholesaler. As soon as it becomes unavailable its taken off the list, but till then its still available for purchase.
Craig and Ben are over in japan atm for TAS and to inspect/buy some cars, so they should be checking it out in person though.