This simple system consists of a machined brass piece that the main jet is installed into. By installing it in-line, the precision sized hole of the main jet provides precision regulation of the fuel delivered to the injectors. And it works.
On F-7 models, it adds 4-5 mph on top end with quicker acceleration. Stock sleds that are very sleepy when you hit the throttle at 70-80 will now instantly come to life and accelerate hard. In 600 feet you’ll see a whole sled length gain.
How safe is it? Consider the Brake Specific Fuel Consumption (BSFC) on a stocker is up above 80 pounds of fuel per hour (0.800+). Installing a 290 main jet into the IP device reduces this to 73-74 pounds per hour (0.73-0.74). Tuners should recognize what this means. Stock 2003 & 2004 F7s use a 280 main, and a 290 if aftermarket reeds are installed. (The safest way to tune is to start with the 300 main jet).
A 340 main installed is the same as having no system installed, so you’re jetting down from that point on. You can still use spark plug tuning and piston crown readings as well as exhaust gas temperatures. If you have an EFI Firecat and want to improve fuel economy and performance but retain a known level of margin, this system has great promise.