Hi everyone! This is a very interesting site. I am new here. I have 2 Audiovox Theras, in case one falls in the horse trough, which it probably will. I am having a lot of fun playing, and now I want a GPS for a trip to Mexico. From other posts and hunting around the Web I seem to find that I am limited to a serial port one that goes into the bottom of the handheld. It looks cumbersome, with cables going this way and that. Now what I really like is the SDIO ones (which also have the advantage of being cheaper) which just piggyback on the machine by means of an SD-card-like-object. Now, I am smart enough to know that I have an SD, but what about an SDIO? Does the Thera have such technology, or can it somehow be upgraded to have it? Anyone who could answer this question would be doing me (not very technologically inclined) a great favor, and if the answer is no, can software for Mexico be acquired for the serial port ones? I can only find Garmin and Magellan software for sure that has detailed Mexican maps. Thank you all.