Recollection is that they want 36 payments' worth of interest out of you for at least 60% of the purchase price. Purchase price being undefined for the moment.
So if you want to put down 40%, finance 60% and pay it off in a year, expect to pay or to haggle over paying 24 months of remaining interest.
For bonus points, see if they'll include a GRV* with your financing.
* Guaranteed Resale Value amount stated up front in writing. Typically requires financing through a Tesla lending partner and typically at a higher rate than credit unions. However, since they're willing to match the rate.... seems that a case can be made for the GRV.
Fine print for the GRV (including but not limited to): Executable only in months 36-39. Amount resembles 50% of purchase price and 43% of options value. Aftermarket improvements negotiable. Miles over 45,000 will incur a $2,500/10,000 mile penalty. Note some owners have been approached for a buyout before 36 months.