Hi there Colin. Im quite intrested in the Mergi stuff you use,but i cant seem to find out anything about it or distributors using Google.Does it make a difference in improving performance too??? I normally fill up with supermarket diesel (Tescos) if im near one cos its cheaper than the main oil compaines,but the downside is its crap fuel.I know im driving a boggo standard diesel and not a sporty hatchback,but my accidental experiment with Shells V-Max diesel proves that diesel quality does make a difference and you get what you pay for.The only bad point was the price of V-Max per litre...it makes your eyes water....a lot... :D I used to toy with different petrols and octance boosters/fuel additives when i had a modified Calibra Turbo.I always ran it on superplus unleaded which made it quicker,but always put a bottle or two of octane stuff in the tank for our trips on Santa Pod's drag strip.Sadly,it died a painful death due to my lead foot and then i decided to be normal & get a ZX diesel...made me feel like i was cycling again! :P