I was under the impression that it was to be priced in the neighborhood of $3000, based on what I'd read on it... I'd not yet seen pricing.
A couple of things to consider, though... the GV units muck up your driveline angles, and they don't mention torque capacity. The Richmond transmissions are only rated for 450lbs/ft, whereas Passon's is very-conservatively rated for 600, which is higher than any of the Nissan or Toyota transmissions (yes, I've also seen where they take far beyond their factory ratings, it's a moot point).
The engineering behind the Passon unit is impressive--preloaded tapered rollers rather than straight rollers? Awesome. Massive gears too. The thing is far-more stout than its rating suggests, but I'm sure it's a measure of Mr. Passon having to draw the line somewhere. The write-up in Mopar Action is excellent from a technical standpoint (as usual); I would not expect any other magazine got as in-depth since they all suck.
One thing about the "fit" issue, though... Kevin has a Keisler TKO500 in his '71 R/T, and it fit perfectly. All the installation parts required came with it, right down to the driveshaft and crossmember. So while Passon is right that "they do not fit!", he's apparently not looking at/considering the complete Keisler installation kits. Oh, and Kevin says it's not likely his 18-spline will ever move from under his bench again, unless for some reason he sells the car. I don't see that happening.
All that being said, I'm still looking for a reasonable Toyota R154 trans (1987-'92 Supra Turbo) to use in the Imperial... I have to cut the car anyhow to put in the stick (I can use all factory parts to do it with an A833), but the handle coming up through the center of the tunnel actually appeals to me since I'll probably run a console. Also, the R154 is pretty bulletproof from what I've read, but then again--much of what I've read dealt with HP rather than torque.