Looking for Heco lab 2 mid-low-rang driver 170 mm

What is wrong with this unit, decayed surround, (semi)fried voice coil, open voice coil? These you can check yourself using a multimeter.

I would first search whether someone is willing to sell the driver only, otherwise there is alternative new units which may replace the old ones provided someone makes necessary mods to make it perform in the same way.

If you have a second driver fully functional, you could have it tested for specs (frequency response and impedance/Thiele Small parameters) which is everything you need to know about it.