I got my 01' SE with 30k on it in 03'... Used Prolong in engine with every oil change as it was my DD (110 mile round trip daily). Going on 197k on that engine and it starts right up, no lifter tick and runs real well. Regular maintenance of course helps. It's hard to find in stores but you can get gallon purchases online for like $100 or so. Also, showing my nephew once that it worked, I changed the oil on my Explorer and with engine running I added the Prolong to the engine and you could hear it quiet down and smooth out, no joke. I used it primarily with regular oil. My GTP gets Mobile1 so no need...
Lucas is good too, used the tranny and injector stuff. Good products.
Prolong Super Lubricants Automotive Engine Treatment