Security Install on a 98

[MCSLegacy]

Hey everyone, so I'm wanting to install a little better alarm in my 98 Legacy GT. Something that really concerned me was the fact that I was able to open my trunk while my alarm was armed. I've got a lot of stuff back there, and wouldn't want someone to get in there.

Unfortunately, my older car died. It was a 96 Honda Accord LX. I decided to take the alarm out of that car, since it's a pretty decent alarm. It's a Python 700. I was thinking I'd be able to replace the stock Subaru alarm with this Python 700. Does that seem reasonable? What is going to be different between the vehicles? Does my Subie have a negative system with the parking light flash? I've never put in a car alarm before, but I'm a do it yourselfer and I've put in MANY MANY car stereos, and custom installs in that department. I'm assuming that a lot of the wires that I'll be connecting to are going to be really close to the factory alarm anyways. We'll see I guess.

Thanks in advance for the help!