Although it seems counter-intuitive, I have not found a Motorola stubby antenna (tried several) that can beat the OEM antenna receiving ability. To get better reception, I have had to use a gain antenna. The ones I have found that don't damage or push in the pin are certain model Kenwood gain antennas. They have the same recess as the OEM antenna, however, they do need the rubber skirt trimmed like the Moto antennas. I use the Kenwood KRA-32K (700-800mhz) on my G5. And the Kenwood KRA-27 (440-490mhz) on my G3 UHF. If you decide to purchase a Kenwood, do so from a reputable dealer, there are a lot of knock offs out there.
I have found all the Moto antennas will push the pin lower, and even had one take out the pin when removed. If you put a Moto antenna on and leave it on, it is not a problem. But if you regularly change antennas, the pin will be lowered to a point that the OEM antenna will not make a good connection.