So that sounds like they have the earlier 93-03 style spring perch on the Legacy tophat.
You would need to install an 04+ Impreza tophat to use 04+ style springs on it, which might not even work - a 97 Outback might be old enough that the stud pattern is different and you'll have to drill out a new hole for the later stud pattern. Easiest way to check this would be to try and put the rear strut tower bar on and see if the holes in the mounting plates line up with what the Legacy has already.
Front studs are the same across the cars so I bet you can use the camber plates.
I'm told that you can use the front bar from some earlier Legacies in the 02+ Impreza NA wagon, but I haven't tried it myself. I have a Legacy 22mm front bar that I've been meaning to try in my 03 when I get a chance.
Whiteline's catalogue counterindicates for it, but Whiteline's catalogue has cost me a lot of money over the last few years by being wrong...
The ALK is probably portable. If it's not, sell it to me and then everyone will be happy.
Tranny mount and trans linkage bushings should all carry across, I doubt that's changed significantly as long as you're going 5-speed to 5-speed. You might have a leftover bushing or two since the 97 Outback probably has an external return spring on its linkage.
