Before you spend the money, are you sure you really need one of these? If you do, I have a couple of friends who are long haul truckers who say they do work. However, I looked at getting one a few years ago and decided to try the less expensive option first. From my very first 3 w bag phone I've always had external antennas on my cars, most of the time with handsfree kits. When I got my current Razr v3m I was disappointed to learn that for some reason Motorola hadn't made the connector strong enough to attach an antenna lead. At that time Wilson sold several several "connectors" which only needed to be in proximity to the phone to send and receive the signal from the antenna. From a friend who saw what I had and needed something similar for his own phone, I understand Wilson is no longer selling these. At the time I bought mine, it was the same as what you could by with the amplifier in the NON direct connect version. I find when placed next to this connector my signal strength increases significantly, on my phone by several segments. I can only suppose that if I had the ability to do the direct connect it would be even better, as in all my previous phones. For the hands free ability I am now using a Parrot blue tooth unit.
So, back to whether you really need the amplifier. When you connect the antenna do you see an increase in signal strength when you are in a area where you don't otherwise get full signal strength? If not, are all the cable connections tight? How old is the antenna? They do lose signal strength over time. I'd make sure it wasn't just a loose connection before I spent the money.
The other issue then is where are you losing the signal? Is it a matter of being out of range of an antenna, at least out of range with your current wattage, or is the signal being blocked by hills? Normally cell towers are placed about 2 miles apart, depending on how high the provider is able to place the elements. For this reason when I lived in St. Louis Missouri on the second highest point in St. Louis County Sprint, ATT, Nextel and Verizon were all anxious to locate on our property. From my experience in driving through the Ozarks in Missouri, if the problem is that the signal is being blocked by hills I don't think the extra wattage will help. I still vacation in the hills in Missouri each summer, and with the phone hooked up to the external antenna I can pick up a signal, IF I am on the highest point I can get to.
