Done 61k in mine with no additives, goes the same as new.

Specially as i've just had a new turbo & intercooler!

Ben

The best way to extend the life and efficiancy of the injectors is to give it a hard running a couple of times a week taking it up to 4500rpm through the gears.

What about several times per day?

I use millers,well i did

Ive still got a bottle of it left in the shed and keep meaning to put it in the boot so i can use it when i fuel the car

I didnt notice any benefits when i was reguarly using millers

Saying that i might go for the splash of millers every few tanks to try and keep the injectors clean approach