Damn, man, they tried to rip you off. I got mine done (RB25 yoke, 240sx rear section and one piece) for $280ish at Charchun. I’ve also broke the rear yoke (cough, a couple of times) and he replaced it for free, not including the cost of the yoke (~$30). Pretty good deal if you ask me.
Note I don’t know what a Tremec tranny is, but I’m guessing its a american drag oriented tranny. Too lazy to search google… I’d install the tranny/engine and measure the length you need from centre of the tranny yoke to centre of the rear yoke, that’s it.
Back to the RB shit (sorry mini thread jack). From what I’ve learned on the forums, state that the driveshaft is from a 240 and the tranny yoke is just a stronger 240 one, a 300zx one, something (read: LIE, in general say it is USDM). DO NOT say that its from a Skyline, they will almost automatically think that they can over charge because they don’t exist here and for some reason its harder to make. Bunch of bull… but I digress.
Just shop around, there are plenty driveshaft shops around Edmonton, but I personally had a good experience with Charchun.