I'd get comfortable with serial handling on the Arduino first, then look at the issues of interfacing a 3.3V GPS with a 5V Arduino.
I think connecting Tx from the GPS to the Arduino' serial Rx isn't going to be a problem, so if you can live with the defaults on the GPS then you may not have any issues, but if you need to have the Arduino talk back to the GPS, then you may need some level-shifting (which may be as simple as a potential divider) to make sure you don't damage the GPS's Rx input.