For what it's worth, I've tried Stanadyne Performance Formula, Millers, BP Ultimate, Shell Diesel Extra etc in my PD130 and ......... none has made any real, repeatable, measurable difference in performance or economy.
I just fill up with Shell now 'cos it's my nearest and cheapest filling station. Save your money ....
If you're worried about injectors getting fouled / dirty, just take the car out for a blast, keeping rpm above 3500. That'll do the trick