As the title of thread says.......... I know this has been mentioned many times on here but I couldn't be @rsd to search for the threads..... ..... I must say I can notice a difference in the torque. Not done the motorway trip yet, just a tootle around and flooring it for a short while (2nd and 3rd etc.) and it does seem to pull quicker and with more ooomph (it could be me imagining it though - only my first tank full so need a few more I guess) So my question is (money not in equation here - 100.9 p/ltr - same as Opti) - your thoughts..... If Opti is cleaner and better for the engine - do I fill up 3 - 1 in favour of tesco 99 RON and every few tank fulls, use opti - or is that not worth it as 1 tankfull in 3 wont make a difference.. ? Thoughts ?