I just bought an 2007, and I heard that there is an alarm for it. So, if anyone tries to open the door while it's armed, it will go off...
Not sure about breaking windows though...

How many ppl keep their s2000 protected with OEM alarm?

 

Yes, you can get an alarm for it. You are probably better going after market, though. Better bang for the buck.

 

I had the OEM alarm but it wasn't sensitive enough.

Viper with proximity sensor.

 

get an aftermarket one, i think it's a lot better. My range is a lot better than my friend's OEM. Plus got remote start (not my idea, they put it on even though i said i didn't want it... but o well, it's come in handy), 2 way lcd is nice too.

I've used DEI products (the company that makes Viper, Clifford, and other similar alarms) for years, they worked well. Now i'm using a Compustar system and i gotta admit, i like it a lot better than my old Viper system. The range on this thing is amazing.