2008 Altima Coupe Security System Question

[altsquirrel]

Is there an available product that will let me add an impact sensor to the factory security system? Altima Coupe 3.5SE 2008.

I've found the exact product here that I want: http://www.courtesyparts.com/nissan-veh ... _7627_7629&

But it states only for 2009+. I need something to prevent break ins and the factory security system is horrible. A thief just breaks window and steals head unit while the owner comes out the next morning to find a vandalized car and the security is still activated! Had that happen with my last vehicle. I figure an impact sensor would at least set off the alarm before a vandal has a chance to steal anything.

If not, what's a decent aftermarket alarm system that integrates with these vehicles considering the IKeys?

Thx!