If I'm not mistaken, and someone please correct me if I'm wrong, Mr. Fink was quoted somewhere (ANR&P perhaps?) as saying that the first batch of SD40-2s (600-609 I guess?) was purchased for $100K each. I can't seem to find the original quote, but my vague recollection was that it was when he spoke at a meeting in Rockland, Maine a couple of years ago.
Considering that demand for SD40-2s has slightly increased since that time, with many of the Class I railroads now choosing to keep them and rebuild them, I think it's not unreasonable that good-quality ready-to-roll SD40-2s with safety cabs would go for $175K each. One would also expect that the price is probably negotiable, especially if the buyer wanted to acquire more than just one or two of them.
Last but not least, consider that they paid about $230K each for the GP40-2Ws when they bought them in 2000 (source: page three of
this document found on STB.gov)... and keep in mind that GPs of all kinds have become significantly more expensive since then. In that context, $175K for an SD40-2W seems like a great value.