I'm buying a new Lexus and when looking on Lexus Financial Services site they list their best interest rate at 3.9% for a purchase for a 720 FICO, however, under special offers they have a 0.9% rate where they say "only a limited number of customers will qualify", intrigued I contacted the dealer to find out the requirements and he stated that it would take good financials and a 690 "Beacon" 
or better to qualify. (My EQ FICO is over 800 so it really doesn't matter) I'm guessing that's "Top Tier" though.
from my experience with NMAC - I had a 663 prior to purchasing my Murano. The total financed amount was just under $50k due to extras (GAP insurance, extended warranty, dealership maintenance program, tire warranty, etc). Since I had never had a loan in this amount, I had to add my husband to the loan as a JOINT applicant (not co-signer) since he's had loans of higher value.
Of course with everything else credit - YMMV 