I'm guessing the "Professional Series" is the "2 Step Fuel Injection Cleaning" they do at Walmart now.....my local WM previously performed a "GumOut 2 Step Fuel Injection Cleaning" but has now been replaced with the valvoline service....figured it was time anyways....even on the Gum Out website they don't display their "2 Step Fuel Injection Kit" anywhere....lol. Sure, it may be a "professional line" item, but still could display it on their online catalog....but eh....I've not yet had the Valvoline cleaning done.....I heard it works good though. Something that has me thinking though, they claim the Valvoline kit is "No Smoke"......whereas, the old Gum Out process produced hella smoke (similar to that of Seafoam/MMO/water down the intake....) so I'm kind of curious what they were able to change to not make it "smoke" out the tail pipe.....
Both products are applied in the same method, it's similar to that of an "IV drip" that you carefully set to dribble through one of the vacuum lines (typically the PCV valve or brake booster line...) without killing the engine, or flooding the engine....takes about 10 minutes for the intake process to run it's course, then the other bottle just goes into the tank to clean out the tank and fuel lines.....