I apologize; I had looked at the amp and not at the "system" they are selling. To use such a setup you will need to separate the transmit and receive antennas as far apart as possible. If you mount the antenna on a rubber roof you should mount a small metal plate on the roof to act as a ground plane. I have my antenna mounted on a small piece of stainless (the kind that a magnet will stick to) which is attached to my fiberglass roof with the kind of tape used to attach automobile trim moldings. Both the antenna separation and the ground plane are important factors that affect how much benefit you actually get from the system.
One thing to consider before investing in this, however, is that it will only work with Verizon 3G and not 4G. Even though you may only have 3G today it is very likely that the next time you replace your phone you will end up with a 4G one. You may not want to purchase a system that essentially is out of date before you buy it.
I have one of these amps on a shelf gathering dust because it is not compatible with my 4G phones (this same amp is often used with a direct connection antenna which is what I originally thought you were going to do with it.) I switched to using a Sleek when I changed to a 4 G phone.
