It is indubitable interesting car, though I am not sure that it should be GTA topic as it has almost nothing to do with GTA, GTA SA, GTAJ or even with GT Am (as it is always associated with GTA series). I will repeat my opinion that the price is high for such a car, (I don't understand why it is considered "prototype" as there is no trace of that project in AR archive), suitable for collection, some AR museum or just a curiosity. I do accept that it was produced at Settimo, (though the body is pretty old to be honest), but it has no value for historic racing and is far away from GTA story. Anyhow such experiments were common in those days and Chiti personally never lost opportunity to try new solutions. I have heard Bonini speaking about very interesting projects as indipendent rear suspension GTA tested by him at Mugello for example. Giulia 1500 engine with four valves was tested with flat and HC head chambers, single and two candles as it was possible solution for F2, and was also majored to 1700 and 1900 ccm, with different solutions. All these projects are known, and 1500 single spark four valve engine was used also for nautical racing as 1500 EB 91 (EntroBordo-in board) and has obtained some WR if I do remember well. AR was constantly present in boat racing from 1937, producing stright 2600, and also star engine for racing boats, and also one Montreal V8 engine was ellaborated for boat racing. Some of these engines were made by Autodelta at Settimo. The rear suspension of 1500 "prototype" is just simple rear suspension of common GT, certainly not suitable for racing. For dedicated followers of AR curiosities, here is the boat with Giulia engine and also Giulia 1500 four valve head of the same engine.