Well, I think Shell fuel pings a lot due to their additives that causes the lack of complete combustion. When I use its RON95 on my stock 4g13, it do feel more fuel saving but I could hardly rev my engine to 4k rpm, try also might can, but the engine will roar very loud but still don't feel the acceleration and power kicking in. V-Power 97 had complaints nationwide, its not surprising we are getting the same quality of fuel instead of the massive advertisement on how good it was by Shell itself. The only perfect fuel I ever used is the V Power Racing, other brands of RON97 are so good too but not the Shell Fuelsave 97. It really feels that that crap RON95.
Btw, in urban areas, there are cases where the fuel stations are using illegal fuel, happens to me where I always saw fuel lorries without any manufacturer's logo at the place I studied once. Usually at midnight only saw such lorries. Also, certain Shell stations are giving away double to four times the Bonuslink points than the amount you pumped as an initiative for you to use their fuel... It always happen to my friend, RM50 for a RM200 worth of points.. XD