I'm a FiTech fan. Replaced a new Carter 625 cfm carb (after repeated efforts to make an older Carter 625 and a AVS I had on the shelf work) with a 400 hp rated FiTech and it's GREAT.
The vehicle (notice I didn't say car

) is the V8 Miata in my sig. Main issue I had to solve was fuel boiling in the carb due to the engine compartments high heat (small underhood area, full of V8) the ethanol contaminated gasoline caused fuel to boil at low speed. FI completely solved that problem. MPG improved and the seat of pants dyno says hp increase too. That along with instant starts and great idle to wot response with no hesitation makes it a win/win.
On the return line, I used the original fuel line for the return and ran a new nickle copper fuel line supply line. Easy. I really don't see any reason to spend the money or clutter up the engine compartment with FiTech's Commander (eliminates the need for return line) system.
Good Luck reguardless of the system you use.
RonR