Answer kinda depends on what you're doing with your "$100k" in savings. If it's really just in a savings acct, I'd try and finance as little as possible because the APR% for the loan means you're loosing money...unless by some miracle your savings acct actually generates meaningful income.
On the other hand, if you mean that $100k in savings is invested in something that's generating income/profit...for the sake of argument, 5% and your Raptor loan APR is 2%, then IMO, you want to keep more money where it's making more money...rather than taken out.
FWIW, I elected to finance $45k for 3yrs at .99% through my CU. The Rate is so low, it didn't make sense to take away from other pots because they're making enough money to cover the .99% rate.
I concur that all Ford financing is higher...IIRC, in the 2-3% APR range.
As for "affordability" for you, $45k at .99APR for 36mon.=@$1270 per month. Only you can answer that question...kinda depends on your other monthly expenses, doesn't it.