I use Motrlube in all my vehicles (6), two of which are diesels (Jetta TDI, 96 f350 PSD). I was previously using Mobil 1 in all of the gas vehicles and Mobil Delvac in the Diesels. In the gas motors I saw an immediate 1mpg increase across the board and virtual elimination of engine vibration in my 89 F150 (300 C.I. I6) above 3,200 RPM. In the Jetta I stopped having to clean the EGR every 6-8 months and in the PSD I got an extra .5 mpg, no other changes. I run to 15K miles with 2 filter changes on the gassers and 10K with 1 filter change in the diesels. The oil still has alot of life left at the change but I'm not trying to get overzealous. Hope this helps.
Unfortunately, I don't. I had heard about it from a friend who lives in Alberta, Canada who put it in his 86 Saab 40,000 miles ago and has done nothing but filter changes every 10k miles. He had a sample tested at 30k and it came back in very good shape, so he's gonna try for 60k. I'll ask him if he still has the test results next time I speak with him. Here's the link to Motrlube: http://www.motrlube.com Garnet Stacy is the distributor for North America so I'll ask him for test results tomorrow. I hope this helps.
I'm coming up on my 7,500 filter change on my 89 F150 in a bit, so I'll be sending a sample for testing then. I had it tested before at 10,000 in my wife's cougar,(came back very good and close to 100%) and recently in my T-bird as 15,000, but I misplaced the results when I gutted my garage to install a lift. javascript:void(0)I'll post the results as soon as I get another sample tested.