The VISA posted rate for today is 20.775. This will be the rate you get at an ATM today. If the rate holds for today, you might get closer to 21 tomorrow.
I never found it necessary to have a Mex bank account. My US bank accounts give access to ATM's worldwide. If you do open a Mex bank account, watch it like a hawk. I had one and evidently the balance fell below $1000mp and the bank ate the remaining balance down to zero with fees. I went in to close it and it had a negative $800mp balance so I just walked out.
You might try wadding up paper towels and soaking them with cooking oil. I keep several in a ziplock bag and they work nicely to light charcoal fires. No petroleum odors.
Awhile back we had a 2005 Toyota Rav-4 that had been in Mexico its entire life. I looked under the hood and found that it had a US EPA and DOT sticker. I am supposing I could take that car to the US and get it registered since it met all the US certifications and was originally made in Japan.
11 years ago our US car was rear ended by a large truck from Galvez construction and our insurance co at the time thru Parker declared it a total loss. They gave me back my import sticker and a letter that said the insurance company took ownership of the car and holds me harmless from future liability. And gave me the declared value.
When we were there, especially in the snowbird season, I would drive from Ajijic to SuperLake or Pancho's either before 9:30 or after 4:00. I hear from friends that the barriers for the bike path have not helped and left turners hold up traffic.