I don't think those guys know what the heck they are talking about. The Tec3 is far from obsolete.
All thats needed is send it in and have a simple upgrade done to make it the same as the Tec3r, which also is far from obsolete!!
$1,500.... I don't know. I would watch eBay to see what they go for. I bought my Tec3r, with all you are advertising, plus I bought a spare 3 coil DFU, and another complete harness set for less than $1,500, brand new....
Give it a go... see how it goes. You can always lower your price...