Crimestopper 2-Way AM Alarms Worth Having?

I am looking @ Crimestopper alarms. My question is are the 2way AM alarms worth having? Will the signal travel thru the walls of my apartment building? I've decided that I want either the Securcar CS-2004DC II or the CS-2004TW1. They can be seen here: http://www.crimestopper.com/index3.html. The reason for this particular model is I have no need for remote start. And these seem to have all the features I want without paying extra for the r/s feature. If anyone has any experience with these type of systems, your input will be greatly appreciated. If the am 2way is worthless, I will go for the CS-2004DC II.

I appreciate the advice. I've had a clifford on my bimmer since '96. It was great while working, but it stopped working all together in '01. Not quite sure why, but I think it had something to do with my alternator going up & having to hot shot it over & over. Any idea where I can orger DEI products on the web? Every retailer around here wants an arm & a leg.