Chef, That is about the right price for a rebuilt tranny. George at 944Ecology is about the same.
I had mine rebuilt by Cattellus Engineering in 2006 for $1860 plus shipping. I have a LSD tranny too.
If you want sticker shock-go to your Porsche dealer and ask them how much a new one costs.
I don't understand why anyone would put money in a $75 car. Start adding stuff up once you are in there -