Shell or BP do make a difference BUT the cost is higher too,about 10% .The
power of my 740turbo is much greater and as it pings on standard petrol or
gas ,I use the 98 octane to give a bit of stick as well as synthetic oil Bp
NOT shell .The range is supposed to increase by 10%as well so its an off set
on price I guess .I have heard the mechanics can tell if your using optimax
or Bp ultimate because the engine is cleaner inside same with Synthetic oil
its much cleaner inside and runs smoother .Certainly no issues with the
engine crudding up as with dino oils .Now the issue is 0-30 oil 0-40 oil or
5-50 oil which is best year round .The 0-30 seems to be a good choice for a
cool engine with less friction but is it wise ?