Same length of time as a regular report. 7 years for baddies on accounts, 10 for BK7, 7 for BK13. Not sure how long liens or judgments stay on regular reports, but whatever it is on regular reports it's the same on the auto.
Essentially all auto enhanced is is a different FICO formula. You don't have multiple files. Uses the same file and runs it through a different formula.
Unfortunately we the consumers are unable to have access to our own auto scores.
Yes, there are many ( 50+ ) variations of FICO scores available to creditors, none of which we are able to purchase, with the exception of the FICO Classic Score.