This is a comparison of the setups i have been running all based on me using a tank of fuel and driving between 58-62 on motorway.
Usual trip is 80 miles a day 40 each way to work.
Standard Plugs, 1.8 Coils, Remap + Shell V-Power = Around 520-570 got 46 odd mpg most days but best was 47.7(Some how)
Standard Plugs, 1.8 Coils, Remap + Shell Fuel Saver = Around 420-480
1 Step Colder Plugs, 2.0 Coils, Remap + Shell V-Power = Around 440-480
1 Step Colder Plugs, 2.0 Coils, Remap + Shell Fuel Saver = Around 500-565
The 1 step colder setup has far better throttle response with the v-power and 2.0 coils, so if your after power it's a nice setup. From the point of view for getting the most miles out of the setup the fuel saver seams to be better i am guessing due to the plug running colder and the lower detonation point helps unlike the standard plus with v power where the plug runs hotter at the same speed hence the better mpg on the original setup.....hopefully your all following this!
From the fuel point of view i have just been looking at the receipts i have lying around....all of these are around the same point give or take a few litres either side. The one receipt i was looking for was the one after the 570 miles for the V-power as that was quiet an eye watering amount to fill up with.
Fuel Saver - 50.78 litres @ 1.349 = 68.50
V-Power - 51.71 litres @ 1.489 = 77.00
Personally i would rather run on the V-power but from a costing point of view if your not arsed about keeping the right foot down all the time Fuel Saver can
help you save the £££......be it not much but if for instance say every week you could save £8.5 a fill up and £34 a month that aint to bad, you could treat the mrs to a meal or buy a new game lol
Before anyone says why don't i try tesco 99, i used to use it all the time but the car didn't run well on it. Now i was going to drop the old plugs back in at the weekend to see how many miles i could get from a tank with the 2.0 coils and give a comparison across the 3 setups but i depends on how quick i get the wiper motor off without smashing it up.