I want to know if it makes a real difference or if I waste money and they have a lot of kind so which one work well with the stock engine thank

 

Stock engine just use high test pump gas. You will lose power going to race gas.

 

Stock motor, use Ultimate 4 if you want to run VP gas. It's expensive and oxygenated so you'll have to go up a few jets sizes to compensate. Some have said they noticed good gains, others, includeing myself, don't realy see a difference other than the smell.

 

Ultimate 4 runs at about $10 a gallon. I personally like vp red the best.

 

I use a mix of Sunoco Race fuel for my stock motor. It is called MO2X which is designed for ATV/ dirtbike engines and has an octane level of 112. It also has lead in it which is good for the engine. I only mix it 20% MO2X and 80% ultra gas.