Hi Jari...
I've been reading up on all the responses you have gotten and I will try to give you some fair advice. I own a MB & BMW body shop in the Los Angeles area and quite often I see these issues occur between buyer and seller. Especially with the amount of cars that are salvaged here in SoCal. CarFax does not mean much...All the entries in CarFax are done by smog stations and Insurance companies - CarFax has nothing to do with DMV! 99% of the time the attendants at some of the smog stations are illiterate - no joke! They either add a zero or a 1 in front of the reading...As far as the legal side is concerned, you may be out of luck. The car is older than 10 years - it no longer falls under the Odometer reading act...So if the seller turns the miles to 19K and tells you that the car is AS IS - no WARRANTY - even more, you took it to a shop to have it checked before buying! As far as the seller is concerned - you have nothing on him...Believe me, it's not worth he agony and the time...I think you should fix your car. Forget about the shop in Los Angeles, I don't think anyone is going to cover for the work and then go after the original owner. Especially here in Los Angeles! I am sorry to be so blunt but the way I see things is exactly the way the other shop owner sees it. One more thing, Ca DMV will NOT release the information on prior owners. Good Luck!