I've been involved in amateur racing for a long time, and I've built, bought, and sold several race cars.
When you factor in the labor (especially for them, since they're a dealer and probably tracked every single minute, at shop rates) this thing probably did cost 60k to build. But the thing is, You will never sell a racecar for anything CLOSE to what it cost you to build. Maybe half, if you're not considering labor.
And the thing with this mz5 is, it's not even a racecar - it doesn't have a sanctioned series to race in. It's a (very well done) track toy, that you can take to HPDE's and the occasional "run what ya' brung" type event like the One Lap, and that's all. That brings it's value down even further.
I think the most they could realistically expect to get for this thing is like $20k. :/