I spent 18 months using Shell Vmax but was getting peeved with the price difference between Tesco momento at average £1.38
And the local shell garages from £1.44 to £1.46.
After a couple of weeks on Tesco (and clocking up the miles going to events) I had a few problems with the car.
Nothing to do with the fuel but a sticking waste gate and fast racing revs taking an age to come down after gear change in traffic.
Intercooler was extreamly hot.
Don't know why but I went back to shell and could be shere coincidense but they car did not feel so lumpy.
This was pointed out by a mate who often comes out to the meets.
I am fully aware that the waste gate sticking is purely Mechanical and fuel would not make a difference, but overall it really does handle better. Remember guys I am not a grease monkey but slowly learning thanks to peeps on here:)