i use kc venom max fully synth on all my buggys,25:1 to 32:1 ratio.tried the high octane shell v power with this oil and it didnt make one bit of difference, i almost thought id lost power,well that was with my stock 28.5cc,maybe better with a ported/tuned engine, but i really don't know.well ,Ive never had a problem with the venom max,the first bottle i ever brought was the venom rock oil but then my local hs changed their stock to the fully synth. i wouldnt mind trying other good oils.the castrol( mentioned above) was recommended to me by someone whos really clued up in this area.mentioned he can tell when an engine has been used with castrol .