Hello Alonso,
Yes, as Marius said, you can adjust the voltage levels of UART3 on Lisa/M v2. Keep in mind that some GPSs, while accepting 5V power due to a regulator onboard, do NOT accept 5V UART levels.
The patch antennas tend to have higher gain, but are more directional and thus are required to be more parallel to the horizon to work correctly. The helical antennas are a little bit more effective omnidirectionally (I think?), but they also claim to have better out-of-band signal rejection to reduce interference with other rf signals on your vehicle. I have used both but can't seem to tell a different really.
The only concern I would have with the Hobbyking one is they did not integrate the antenna onto their PCB; instead they use a short pigtail to an external antenna board that is just stacked on top. Each connector introduces potential mechanical failure points - in a high vibration environment this might be an issue. As well, each connector and length of coax introduces loss into the system, reducing the sensitivity and effectiveness of the unit.
Shameless plug: the Paparazzi designed ublox GPS module works well and has been proven over a number of years, and is available from PPZUAV. If you ask nicely you might even be able to get a cable made specifically for your autopilot (not sure though).
Hopefully that helps a bit.
Thanks,
-Stephen Dwyer