For me the VIEDS did not work well. Could never get rid of pinging. Fp3 solved my issues, much more to a good tune than adding more fuel.

 

Exhaust is not the problem, air intake is. The more air the richer the map needs to be.

 

I tried them on My 2014.I ran at 100%.Then I installed an FP3.First thing I noticed was how smooth it accelerated.Ran some autotunes and set the AFR to 14.0.Great performance and stiil got 40mpg.Then I got bit by the M8 and had to have one!

 

I bought into them and found the product to be just a gimmicky pile of wires. I adjusted them as per instructions and didn't see any difference. The reason I bought them was for the 20-30 mph "Harley head rocking surging". Tried multiple adjustments leaving it set at a particular mark for days at a time to let ECM enough time to learn the new afr.
The only setting I noticed any difference was at max. The bike was like it was drowning and lethargic so I knew they were at least doing something.
Took them off.
Decatted header, Fullsac CVO 2" cores

 

I moved up to a full tuner with a cam swap in my near future, so I got a set I'll sell