Speedwagon8

Ok, so I'm a bit of a newjack on Scoobynet. Didn't ever really bother to come over here, as I stayed on the US forums. After browsing through here the past week, I've realized I should have come here a long time ago. Anyways, to my point...

I have a 98 US Legacy, with the 2.5 NA engine. The computer is OBD2 obviously. I have a 91 Japanese EJ20 turbo engine that will be going into it, from my former(may it rest nicely, it was a good car) 91 Legacy that I owned while in Japan. When I took the engine out of the car, I took everything with it. To the point that I could assemble it, slap on a battery and gas tank, and it'd be good to go.

So, this engine will be going into my newer 98 now. But, I'm not sure what route I should take for the management issue. Support is more limited here in the US, as they haven't been doing this quite so long on Subarus.

Options I've been thinking about are as follows:
Use the stock 98 computer, and add a piggyback. Something like an AVC-R with S-AFC.
Use the stock 91 computer, and do a bit of wiring work to the 98 to slap it in. Use this in stock form, or add something like the AVC-R again.
Add a more advanced piggyback to either one of the computers(UTEC is pretty popular around here).
Get a full standalone computer(though again, not really sure which one works best for my situation).

Wiring doesn't scare me, and I have no problem hard wiring a computer in. I really just want something that will control the engine well, have some room for upgrades, and something I could get some decent support on. I'd like to be able to tune it myself, though I know that might be a bit far off for now. Good tuning is not easily achieved. Any thoughts on this?