I'm about to pick up an oem alarm off of an ap1. is there any difference in the ap2 OEM alarm?

 

I believe they are the same ...

Just get an aftermarket one, and a nice install job. OEM alarms are so generic that anyone who's willing to bother to check out the install diagram could defeat the system in a very short period of time.

 

do those alarms (oem) just plug in or they need to be wired up too?

 

It's more or less a plug-in type of thing.

The OEM alarm is placed under the driver's seat. And the system should come with a wiring harness. The harness just runs from the kick panel to the driver's seat (requires removing some panels, but nothing hard).

Here are the instructions: http://www.handaaccessories.com/S2000/s2000security5.pd

As you can see, the system is quite simple. One could probably guess where the disarm / override switch easily (since most people would place it under the dash as instructed by the instructions). Also, the alarm will be placed under the seat. Just takes some force to break or cut all the wires even if the car's in the dark.