Chris: Minisplits are available in 110 volt. Many of the small tract houses actually have a 30 amp 220 volt service.
Warranty? Just try and get that from a small builder unless you have a holdback
Pipe: In Canada and the USA water pipe must meet a standard. It is either UL or CSA or some other testing standard. Ordinary PVC water pipe in Mexico is very thin and has no standard printed on the pipe. It is junk. Schedule 40 is available and is marked as such There are many electrical items for sale in Mexico that do not meet any standard. Those 100 volt plug in devices that you attach to a shower head is a good example. They are dangerous and a person in our town was electrocuted from that device. Home Depot, Lowes and the electrical/plumbing stores do carry approved items. Cheap contractors don't shop at those outlets. There is a reason why some stores advertise items as Calidad de Exportacion. The best stuff is exported NOB. When my Plumber or Electrician in Canada does any major work he takes out a permit. The inspector may choose to visit the work site before any work is done and he explains how he wants the work to be performed. Or he may choose to inspect after the job is done. Neither inspector takes mordida. Tradesman in Canada and the USA are required to attend classes and upgrade their "ticket". I will take some photos of really bad workmanship when I return to Mexico and post a few. They are shocking (pun intended).
Moisheh