I wish I still had Brian's G tech. I'd average a few 0-60 runs with Startron and then without. Lets see what the numbers say!
I think a lot of these additives have a bit of a placibo affect. I have run a bunch of them in the SDL and didn't notice a difference. Then again the injection system in that car is in top shape.
I remember when I wasted my time and money diesel purging the SD. The DP came out of the return line just as clear as it went in, no change in performance.
Now I just pull the injectors, have them tested and fixed if need be. It gets results, I like results!