It is actually less than that.. I obtained the lens for 190 US$, but the postage was a bit expensive... and $15 for M42-EOS adapter (ebay).
Machining was done by a friend (yes, he is still my friend, despite all those jobs done for me in the past.. and there is no hope I will stop doing those things in the foreseeable future
)
Yes, I am pretty happy with this lens. It would be interesting to compare it with some specimens from "L" series.. just to see the real cost of eventually better performance.
Of course, here I have manual lens only, which would be pretty hard to use for terrestrial photography (no AF, no IS etc).
Also, because the mod is not reversible, I am not sure if I could sell it again.. not that I intend to, though .