I have been putting a can of this stuff through my wife's Pug 207cc Sport - turbo, direct injection, at every oil change.
Once scored a dozen for $120 from eBay.
Reason - to combat the carbon build-up on the inlet valve stems, a nasty by-product of direct injection.
Initially would throw a code and go to limp mode. But with my trusty $20 Chinese diag tool I could always erase the code.
However, for the last four oil changes, doesn't throw a code at all. Just goes to show that the gunk is being removed.
Never used it on the Red Jett - with catch can, etc.
So did it at recent oil/filter change (136,400 odo).
After start up, a reasonable amount of expected white smoke out the back, then sprayed the remaing SA459 into the intake manifold, not through the throttle body.
Result:
Excellent idling. On cold startup the Red Jett was always a bit cranky with it's Jim Wolf cams. Now, no conk out. Also a fine addition to a smoother engine acceleration.
I'll do it every oil change from now on. Sheeese.. That will be 1st june 2018 - as the Red Jett only does 2,000 klicks a year now.
If you need to know how to do, just holla'