Diffuser: This was easy to install.
Front Splitter: Be sure to test fit the splitter with the spacer located on top of it so you can determine where to drill the tow hook holes.
Brake Intake Ducts: These were easy to install.
Brake Ducts: These are considered a very tough step, but I don't agree. I recommend installing them BEFORE installing the sidepods so you have easy access to the cutting areas. The only hard part is getting the edge of the duct to line up perfectly with the sidepod hole. You have to continually test fit and remove fiberglass over and over and over. The 2nd side goes much faster.
Side Scoops: These were easy to install. When installing the A/C condenser, I removed the right side scoop to make it easier to work...but then reinstalled it before mounting the condenser.
Side Splitters: These were easy to install. The dimples under the sidepods lined up ALMOST perfectly. I wouldn't trust them without testing fitting.
Dive Planes: Super easy to install. Measure twice to make sure you have the right placement.
Rear Wing: This was not as difficult as it seems. It does take several hours, but that is mostly due to the difficulty of getting to that area, especially if the rear mesh is already installed.