You're in Luke's neighborhood and he has been around for along time. He knows what he is doing and you will find that you don't want to take an alarm to someone that doesn't have a proven track record. Not too many people/DIY'ers are willing, much less capable of installing an alarm even remotely close to the correct way. Even mechanics regularly bring their vehicles in to have alarms installed professionally.
I explain it to customers like this, if the alarm saves you just ONE break in, you will have recouped the average cost of it just by not having to pay for the damage alone that they will do to your vehicle on the way in. Not to mention if they get anything and the losses incurred with that.
And, most insurance companies will give at least 10% off your yearly premiums if you take the shop invoice and vehicle to them for a post-install inspection. You can recoup the cost of the alarm within 1-3 years just on insurance savings alone. Not to mention the peace-of-mind you get with having that safety net installed!