It seemed to have eliminated my cold start exhaust richness in my minivan odor-wise (hmm .butt dyno - but "butt sniffer" just doesn't seem quite right). I've got a 15 year old fuel management system. The economy appears strictly dictated by the miles per cold start ..but that may just mean that the lameness may be a reduced problem after warm up.
I also used it in my wife's jeep after the second high fuel UOA with Terry (one B-S, one with his lab). I can't give an conclusive fuel economy gains yet. Not enough tanks of fuel ..and it's a poor indicator in a jeep. The drift can be between 17.5 and 19.5. I may have had one 17 in there somewhere (memory is getting strained here). Out of tune for us appears to mean downshifting sooner
This was after a full tune ..so I didn't notice any "profound" effect after use. If I still get high fuel ..I'm probably looking having the injectors refurbished and flow matched. I'll probably try Amsoil PI first.
My cousin placed an order today for 5 gallons of 10w-30, comes out to $7.10/quart without shipping and there is no sales tax. He's a nit-picker so we'll get a uoa posted as soon as he gets some miles on it.