I put them in during my RV-4 build, so it was very easy. If you aren't a "builder", It may be challenging, as it's not a bolt in operation. The R/H tunnel web has to be modifiied and cut, you will need the entire center floor removed, and the VANs supplied weldment/control arms require a second set of nylon pivot blocks located/installed. There will be a hole through the belly skin for the bellcrank arm pivot bolt and brackets for the actuator. While not complicated, it's got quite few moving pieces. There are quite a few RV-4's with a homebrew much simpler retrofit which installs the actuator vertically in the R/H sidewall and ties into the existing weldment, but the VANs kit is less intrusive to the passenger environment. I have my flap control buttons on my stick grip along with aileron and elevator trim...I LOVE the HOTAS system and never have to reach for anything on the panel. I also built close-outs for all the interior areas that have moving parts, and here is no flap handle for passenger foot fouling. You can see most of the parts in the pictures. I probably have some better shots in my build book, but it's not with me at the moment.
