It's V Power, not standard 95RON unleaded. Heat from me.

It's a higher octane to the Asda £1.07 fuel, 99 vs 95.

This is just not true, both for petrol and diesel. For petrols you will get better mpg and for diesels it'll keep your injectors clean. I wouldn't put the good stuff every time but one in every 5-6 tanks, I put the good stuff in my diesel and it does help me return better mpg. Can't advise on the petrol but at the very least it'll return better mpg, especially if it's a performance vehicle. I have to admit it's unlikely you'll make back the difference in fuel price with your improved mpg, but for the diesel, that isn't the primary reason I'm doing it. I have colleagues in the fuel additives business so don't lump me in with your usual car forum reading know it all. Just so you know, for the diesels it is the additives that make the difference, the base diesel fuel is much the same everywhere. Cheaper fuels contain a mix of either cheaper additives, or just less of them. They do help keep injectors clean, but you have to be careful as badly deigned additives can actually damage your injectors over time too. I therefore advise against the additives you see in places like Halfords. If you want, just buy the better fuel for a bit and put in a few tanks worth. It'll likely be cheaper and achieve much the same, but more safely.

Per mile I save about 10% from shell v power over supermarket cheapest stuff. I have tested it over the course of dozens of tanks of fuel, and I always get around 10% more miles per pound.

I would use it if it broke even, or was slightly more expensive per pound because of the performance increase, and the benefit to the engine, but the fact it is cheaper by ~10% when you take relative MPGs into account makes it a no brainer for me, plus you get to earn shell v power points as well, so that adds further savings for me down the line

It will depend on your car/bike, but it isn't just performance cars by any stretch. You would be suprised, calculate your avg MPG currently, then switch to vpower for a couple of tanks, see what/if any effect it has on your car. Worst case scenario you lose 3 quid finding out it doesn't work for your car, however running your car on Vpower for a couple of tanks will do it a lot of good, it has a lot of cleaning additives that other fuels don't have, so you won't have wasted the 3 quid finding out anyway.

Good effort.....

Better mileage and cleaner engine, and this is a proven FACT, not necessarily a "boy racer" thing..

Yes, for most cars as you said.

But for people with performance cars it is often justifiable. Modern performance cars, particularly turbocharged ones have learning ECUs that can subtly alter ignition and boost etc after getting used to higher quality fuel.

They can see decent performance gains over 95 octane AND some tests I have seen offer small economy gains. Not much in terms of economy, but enough that you can basically get the extra performance from the fuel for free. Even a 1MPG gain seen in some tests makes the difference in cost per tank small. So there is no reason to NOT have the premium.

I will stress, if you think this applies to your 84bhp 1.2 Corsa, then no. If however you have a 300bhp turbocharged Ford Focus RS for example, then yes, the case for premium fuel is strong.

How're you getting 340 out of your S3? Even more reason for some 9