I have just past the point of going forward with purchase so slightly ahead of where you are now.
@jjrandorin is spot on with the assumption that you will receive full rebate and apply that to your loan lest your monthly payments increase ( I believe Tesla lists amount that payment would increase.)
I was quoted exact same rates for 10 and 20 year loans. What I was not able to get were any fees associated with these loans. If you calculate out the payments there are clearly fees and/or something is being massaged with the compounding. In any event in my case the 20 year was much worse than the 10 in terms of actual amount paid. In my case financing $32,000 almost added if I recall over $20,000 to the cost after 20 years. The 10 year was much more reasonable. I don’t know if this was simply due to the nature of compounding over 20 vs 10 years or if additional upfront fees were in play. I believe as
@jjrandorin stated Tesla is still using 3rd party financing and that is reason for lack of detail loan info.
I believe if you have good credit you can find outside financing on your own for slightly better rates or you can take out a home improvement refi on your home / possibly write off interest. (This would be “cash” option as far as Tesla is concerned). This has been discussed on other threads, some people are opposed to this for various reasons etc.
Personally I went “Cash” am hoping Tesla still allows PayPal or Plaid cc payment when payment due (after inspection approval) I will put about $20,000 on a 0% cc for the points and pay off within about 10 months.
oh and yes in CA you pay tax on all hardware but not on labor.
Sorry for long winded response I just passed this point so fresh in my mind.