This may be a way dumb question. I never got a keyless system with my outback. Did they all come with one? It's a 98. If not, can I add it for a reasonable price or would I be better off going with an aftermarket system?

I'm not certain, but I believe that the factory keyless was an option for that block of years. I don't think it became standard equipment until MY01. Not 100% on that.

 

Subaru uses and add-on module for its keyless entry system. IF yours doesn't have it, then you could certainly get one out of a wrecking yard for pretty cheap. Around here, such things tend to go for between $20 and $50. INstall is pretty straightforward. Attach the block connectors, screw it down. Problem solved. If the yard doesn't have the remotes, they can generally be ordered from Subaru, but they're pricey.

 

Aftermarket systems start off around $70 or so and climb from there. INstall is a bit harder because you can't use the really nice block connectors to wire it.

Grab the unit from the salvage yard. Should be under the driver's side of the dash. You already have the plugs in your factory wiring harness for it to plug into. Buy a new fob off eBay and follow the instructions for programing it to work.

if you pull a security system from a salvage yard be aware you must get it from a '98 or older Legacy. 1999 thru 2004 Legacys used a different supplier for the "factory" (dealer installed) security system.

So.... My 98 leg GT Just so happens to have a factory security "computer" or whatever under the dash. My friend bought an impreza RS that came with aftermarket remote start and alarm. The guy also gave him the factory keyfob and "computer". It's identical to what I have under my dash. So would it be easier to program the remote or just switch the computer thingy?

Just reprogram the fob to your car and you will be done. There is no need to replace the computer. More work than you need to do.

Just to confuse the picture a bit, but:

 

My 2002 Forester came from the factory with the keyless remote.

It opens the doors, as it should.

But there is no security module installed.

 

So the fact that you have a remote, doesn't necessarily mean that there is also a security module in the car.