The best setup going is the hardwired car kit. I have a moto E815 with the s9950a kit in my 98 with a hang up cup made for the phone. On mine the antenna connection is located on the back of the phone so it seats when you put it in the hangup cup into a corresponding connector. That is what the external antenna is connected to, the hangup cup has a 24" pigtail with a mini-uhf connector that attaches to the external cell phone antenna, mine is a thru the glass Antenna Specialists 3db gain antenna and is mounted on the driver side rear window. When I first hooked it up and plugged the phone in I went from 1bar to 4bars that quick so yea, it's worth it.
My 815 is a bluetooth phone and I have a motorola HS850 bluetooth headset, great combination for wireless hands free. Add the hardwired kit which charges the phone while it's in the cup and has it's own speaker that I put under the glove compartment and microphone which I have over the sunvisor, voice controlled dialing the only thing I was missing was a bluetooth equipped head unit, in my case a Jensen am/fm/cd, that will get here on monday or so
I will pair headunit with the phone and put the calls thru the stereo system, it will display caller id on the head unit and the head unit comes with a built in microphone.
The antennas are rated by gain, one that goes on the roof and requires drilling and gets a 5-7db gain, the thru the glass gets a 3-5db gain, the mag mount is -0-db gain as is the candybar type that goes inside the glass and sticks on like an easy pass.
The antenna boosters are a joke, do nothing but put money in someone elses pocket.
Start looking at your phone model and whats available for it.. MIght be time for an upgrade and I can't say enough good stuff about a bluetooth phone, I also upload and download to one of my PC's that has a bluetooth dongle on it, I treat the 512meg transflash memory card in the phone like a memory stick or I can plug a usb cable into the phone and connect directly to the computer. Cool stuff...
Oh, my hangup cup is mounted on a 'vehicle specific mount' made for XJ and TJ's, mounts behind the center bezel next to the radio and leave no holes. Just do a yahoo search on 'vehicle specific mounts', panaflex
http://www.pro-fit-intl.com/jeep.html is the one I have.
