Depends on use also. If mostly town driven against highways driven, highway one sure less carbon, running constant speed and on better air/fuel ratioThe caltex i used to go before i move does not have it anymore. Its either sold out or they dont have it as previously the petro shop is handled by them but now its taken over by 7e, they just have seperate counter for fuel payment.
Doubt that its selling well, doubt any of us here has tried it. Most of us just fill up and go.
However i can confirmed using Caltex on the long run will result in cleaner engine. I did share in one forum before when i gatal buy an endoscope to see the combustion chamber of the cars in my family stable. That time the Wira which is on Shell most of the time until 120k km is having more carbon than my BLM and Waja at above 150k km. Same goes for the Pajero and my bro W124. I dunno where is the pic as i forgot which laptop i stored it in. Even lost the endoscope when moving my stuff to my home.