If you have an agreement written up and it is "Subject to Financial Approval". You could end up owning the vehicle before you are aware that you own it.
One thing I have heard of is having the agreement written up as "Subject to Spouses Approval".
Getting multiple car dealer quotes, involving your bank info, can effect your 'Credit Score' temporally.
The only advantage to leasing is the ability to write off the payments if the vehicle is used for work.