ok, you need the software from dynojet to be able to load maps and alter them. if you have a laptop, you can connect to the PCIII with it, otherwise they sell 9v adapters so you can alter maps on your pc and upload them to the PCIII. As for getting maps, there are 2 ways. 1, find one that someone has that has the same mods you have. Dynojet has some on their site and if you ask around most people will share their. some won't cuz they did them the second way. 2, you can go to a dynojet approved tuning center and have a custom map made for anywhere between $150 and $300 which is why some are reluctant to give away their maps.
how do you tell if one is already loaded into your PCIII when you buy it? I have no clue.