The 44K is good stuff, but just too expensive (and I even get a discount from my dealer) for what is mostly Naptha. Chevron Techron is the same thing (mostly Naptha with polyetheramine added) at much cheaper price. The regular stuff is a relatively weak dilution, so every 1K miles dump in a bottle. The Techron Plus is stronger (and equally more money) and only needs to be added each oil change. They recommend 44K no more than 2x a year. I dunno the comparative dilutions, but I find that my engine could take 44K more often than the recommended 6 month period, so I /think/ 44K and Techron Plus are probably pretty similar chemically. To be safe, I only add the 44K or Techron Plus shortly before an oil change just in case it contaminates the oil.
As far as oil additives, I figure regular changes with good oil and filters is sufficient. If your engine needs additives, it's probably too late. Just my $0.02, really.
