Thanks everybody for your help. I'll try to clarify the issue as best I can.
@Fairtax4me All of the rebuilds I've purchased thus far have been in the neighborhood of about $80-$100. I've had to return 4 units because, while the records the parts store had indicated thy had the right part, it turns out that it doesn't fit. The average price for the used units at the junkyard have been about $40. I've looked at Outbacks and GT's. All have the same unit, but that one isn't interchangeable with mine.
@grossgary The brakes are pretty squishy. I've bled them several times. It feels like a failed MC. Anyway, the unit at the link you sent is pretty close to what I have except for 2 small but important details. One of the outlets is on top rather than the side (like mine) and there's no pushrod attached. The photo I uploaded is a little dark but you can make out a black pushrod on the back. It's about 1/2" in diameter. Those 2 variations are the root of the problems I'm having finding the right MC.
My car has ABS and is a manual transmission. I've been combing ebay for days. Every once in a while I'll find something that looks right but they usually end up wanting over $200. I just don't have that kind of $$ and it's also why I've started looking in the junkyard.
The other ebay link is to a unit I already purchased and returned. They never specified in their list whether the unit is for ABS or non-ABS. I found out the hard way that it's for non-ABS. It's hard to see in the picture but there are also 2 ports on the bottom of the unit.
@MIlesFox Yes, I agree. They *should* bolt up the same. However mine has the pushrod in the back that makes necessary to replace with the same kind of unit. That particular feature is the rarer of the characteristics that I need in my replacement unit. That's making it quite difficult to find the right one.
What I'm thinking of doing is getting the brake booster and MC together at the junk yard and replacing the whole thing. I'll also need to replace one of the brake lines to make it work. (I think the person who sold it to me did some 'creative' work with the MC etc.) Any thoughts on this idea?