I've gone 400 miles (14 gallons) on my first fillup of HPR.. I have a CDI with the I6 OM648 so maybe it is different for the newer engines. I noticed at startup it is instantly quiet compared to d2 at 4am when i leave for work and when i romp on the accelerator i get no puff of smoke like on d2 (or at least it's not as visible). I am going to try and keep using it to see if i see any leakage or filter clogging problems but unfortunately I have to go out of my way to either oakland/berkeley or to sacramento to get it.