This goes for both scenarios.
The lien is recorded with your state when you make an application for a title transfer. You'll receive a non-transferable title that must be signed off and released by the lien holder.
This is their security of the asset financed in the promissory note in the event of default.
One thing I'd suggest is that you ask for a simple interest schedule instead of a compound interest schedule. It'll assist you a little if you go to pay off early on the unpaid principle. A little bit more money will apply to principle to early payments.
If you think your going to take the entire time to pay it off it'll wash the same.