Hi. I was wondering if minelab has made two versions of the quattro? I have seen a minelab quattro on the internet, and a minelab quattro mp. If they are different, is the mp a newer version? I was also wondering how safe it is to buy a "used" detector, even from a certified dealer? I have seen a used minelab quattro on the internet from a dealer for about $550.00. It said that they offered no warranty, which I expected, but that otherwise it is in excellent condition. I think it said it came with the standard 10 inch coil, and a cover for coil. Thank's for any info. or advice. Randy