I usually fill mine with regular from the local Husky/Mohawk. 87 octane and consistent quality fuel. Where as the other station's in town the quality seems too vary greatly depending on the tanker load.
I have had some fillup's when I've used the other stations and the engine will be all over the place severe bogging car deciding too go rev. happy, etc.
Imho, this car is more touchy about needing good quality fuel than most.
Also little known fact but one of the pollutants the cat is designed too remove is N2O or Di-nitrogen oxide so shell enriching their fuel with nitrogen leaves more available nitrogen too form the compound because nitrogen does not burn so it actually makes your cat work harder.
As for their claims of reducing carbon build up your engine shouldn't be seeing too much significant carbon build up unless it's running rich. So benefit's for a DD are pretty negligible. But it does offer some frightening disadvantages.
Replacing a cat can cost oh $3000.00 or more which is kind of ouch inducing.