Just got back from a 3000 mile trip through Washington, Idaho, Montana and Utah. This brings my total mileage on the kit to over 6000. Lots of mountain passes and cold ambient temps for turbocharged fun. The turbo system performed flawlessly despite a few maintenance items with my truck that I'm addressing now. Scangauge reading was approximately 11 to 12 mpg cruising at 80mph on flat ground. While this isn't too bad as far as I'm concerned, I'm switching out my original O2 sensors for new oem and getting my various pinhole exhaust leaks fixed. I was heavy on the throttle in some deep snow near Ogden, and saw around 220F coolant temp on the scangauge. Shut down the engine and let it cool while I winched out. Probably due to high revs at low speed. Maybe unrelated but my front knock sensor failed (p0325) the next day near St. George. With about 400mi to home my mpg dropped to single digits as the engine protected itself by running rich. Wideband confirmed that the ecu was dumping fuel. Burned a lot more fuel on the way home despite cruising at 70 instead of 80mph. Should mention, I only filled up with 91 octane or greater during the trip.
Here are some pics from the trip and a few thousand miles of road salt stuck to the downpipe for science. Don't worry, I washed it asap.
Overall I'm extremely happy with the system and I'll see how the mpg improves when I patch up my janky exhaust.