Let me share a fact about mexican eapis.. If you are a Part 91 operator, you're still not required to file it. The word of the law says "it must be filed on the official web portal of the INM"... and it happens that the portal doesn't exist, so legally, they can not pin you for that. I have personally checked this fact with a couple of friends in Mexico that happen to be Federal Judges, and FEMPPA (mexico's version of AOPA) has actively pressured the government and got an agreement that until they come up with the portal, the cockamamie system the government came up with of emailing an excel file with the data is treated as a "nice to have", but it's not enforceable. With the above said, it's up to you if you want to send the info via email or not and if you do to make you feel safer, just print the email and have it with you; I assure you nobody is going to ask for it since the agents at the airport don't get it; it goes to a central computer on some obscure building in Mexico City and nobody monitors it. Don't ask how I know but I DO know.
Now, if you're Part 135 or 121, that's a whole other story; I'm also a Part 135 operator and the requirement imposed by the government is to file electronically thru Honeywell's ARINC portal, contracted by the government (without a bidding contest, by the way) where you as an operator have to sign up for, pay a stiff annual fee and 260 dollars per manifest, whether inbound or outbound.
These are the facts... Whether you want to follow my advise or not is entirely up to you. When and if such portal becomes available in the future (I doubt it for Part 91), I'll be first to know and will post the information here accordingly, with links to the correct website.
P.D. I fly in as Part 91 so I never file, and the charter fleet goes as Part 135 and we, or should I say our customer, gets stiffed with the $520 per round trip on top of the charter rate.