I've been a regular user of Millers Powersport 4 in all my cars. Never had any probs. Engine runs nice and quiet, no smoke etc etc. MPG is slightly better when I use it coz it increases the cetane rating of the fuel by a couple of numbers, which helps combustion.

Seems to work best with Shell Diesel Extra, which is a good fuel to start with. Adding a bit of extra cetane and some cleaning agents won't do any harm.