Welcome! Please post pics of this car
You don't need to cut out the trans tunnel for a 5speed d/r.
Bratman18 has a linkage.
Check out this website
http://www.ultimatesubaru.org/forum/
It's the old subaru mecca of the internet, really. Everything you can imagine has been done.
If you're looking for subaru parts there's a guy named Ben Vaughan in Coopers Mills. He has a huge cache of old subarus and parts.
I wish you good luck getting in touch with him... he's cancelled his phone and forbid me to give his cell number out to anyone....
Lastly, I have a spare 5mt d/r that needs some work. It has a bad bearing on the input shaft and makes angry noises, also could do with new syncros. But worked otherwise fine when I changed it out. I drove it to and from North Carolina like that.
New bearings it would be good to go if you're careful shifting it... I don't want to part with it. But maybe I would...
Oh, one more thing. You need to either get an ea82 flywheel and clutch kit, or get the ea81 flywheel decked to ea82 flywheel spec (which I can't remember now because it's late). And then get an ea82 clutch kit.
I have an 89 GL I've replaced pretty much every part on. So you can ask all the questions you want... heh.