It may not be too obvious from LetItSnow's picture, but he used a connector and pins I provided that plugs into the SVX's security harness. It will make the job a lot easier (less splicing/tapping into factory wires), since the OEM harness provides the majority of signals you'll need for an aftermarket alarm. E-mail me if you're interested in getting one.
For a remote-start unit, it may be better to mount the "brain" closer to the steering column, where you'll have to tap the wires for starting.
I came up with a trick to wire up the remote trunk release: There's a connector in the trunk to provide power for an ancient-style cell phone (pics and details
here). It's the only thing wired to that fuse (#10). So you can connect your solenoid directly to the cell harness, and build a circuit to interrupt fuse #10 using a relay (perhaps customizing one of those add-a-fuse thingies so that it breaks open the "load" side of the fuse #10 circuit rather than adding a new circuit).
For later SVX's where the security module goes in the trunk, you can simply grab power for the solenoid back there, and wire it through your trunk solenoid relay (which you'll have back there also). In other words, no need to mess with fuse #10 up front.