What are the visa & residency requirements in Lake Atitlan?

"You are allowed to stay in country 90 days before you have to exit country and renew. El Salvador, Honduras, and Nicaragua don't count. So most folks go to Mexico. It is also possible to pay someone to take your passport to the border and get you stamped out and back in. There are people who have lived here for many years doing exactly this. Residency is complex (like almost every country) but if you can qualify as a permanent resident (pensionista) you can obtain citizenship and passport in five years," remarked another expat in Lake Atitlan, Guatemala.