EK alarm swap

Hi all,

I searched around a little and couldn't find anything exactly related to what I'm doing.. Anyway, I have a 00 EK with a JDM B18C, and P73-013 ECU. As I understand, the JDM P73s don't have an immobilizer like the AUS of the same, and the only reason my car has an "IMMOBILIZER" sticker on the window is because the stock car would've had one. I have a pretty cruddy branded alarm installed (ebay job I think) and it's remote range is about 5ft, and the remote buttons are starting to die and I can't be bothered getting a replacement for such a bad alarm. So I bought a Viper 350 alarm from the US, it's on it's way in the mail now. Found an installation manual here
http://www.directeddealers.com/manua...426V_07-04.pdf
I'm confident using a soldering iron and pretty much everything necessary to do the install, I'm just wondering if there are any problems I might run into disconnecting the old alarm and slapping in the new one? Since there's supposedly no immobilizer in the ECU, there should be no risk of me messing up anything and preventing the car from starting, correct? I DO have this
http://www.honda-tech.com/showthread...ht=green+light
light in my cluster when I start the car, but I don't know why since I shouldn't have an immobilizer connected (other than the wire connected to the existing alarm that prevents the ignition from working when the alarm is armed, or if the immobilizer is separate from the ECU in the stock car). I don't believe I have coded keys or anything, they seem to be just plain ones and all I have is my aftermarket remote.
Here's a photo of my key... http://i.imgur.com/gcrU4.jpg

So, are there any problems I might run in to? I can't really afford to have someone install it for me, because as I understand it would probably be $200-300+, I'd much rather save that money and do it myself.

Many thanks