Well, I tried it in two different diesel cars, back in 1998/1999, and we drove more than 20000 miles with this Tufoil.
In these cars, it did not work in any way.
No reduction in fuelconsumption and no noice reduction.
One of the cars, a Mercedes 300TDT, was also going very warm, and no help in that matter, either.
All in all, really disappointing.
If it gives you good results, be happy about it.