I ran my RCC turbo setup with the VRFID, including some time at the drag strip. It works well with the RCC setup because that one uses a rising rate fuel pressure regulator that automatically increases fuel pressure (on a 4 to 1 ratio, 1# of boost increases fuel pressure 4#), and thus increasing the injector output. The VRFID responds to the AFR changes just like a normally aspirated motor and as long as you are within about 25% of the target AFR all is well. If you get to far off, the VRFID has trouble getting the AFR to stableize and will fluctuate wildly from way lean to way rich within microseconds and the motor will miss badly. I had that happen on the rear cylinder at high rpm's and WOT. The data log on that run, for the rear cylinder only was pretty wild looking with big peaks and valleys on the AFR chart. I have had the same thing happen with the big bore setup so it is not isolated to the turbo and it seems to happen to the rear cylinder only.