Welcome to the forum! I too have an '05, but mine is a non-turbo. I love the little car, but like someone already said the mod-bug can bite you pretty hard. I'm not used to having a vehicle that is so easily modified. There's only so much you can do to a Mercedes LOL. I hope you enjoy yours as much as me!
Also, Viper is made by Directed Electronics who also makes Hornet alarms. You may be able to pick up a remote at Circuit City. They carry Directed Electronics products. You probably didn't get the owner's manual to your alarm either....if you can locate the brain of it and pull the model number, you should be able to download a new owner's manual as well as programming instructions for the new remote here:
Directed Electronics - Security & Remote Start | Home Theater | Satellite Radio | Car Audio & Video