is it possible to have a too higher octane level for your petrol..i.e using optimax and also something like hot shot or nos octane boost?

you could but im sure justing that much octane will damage the internals in your engine.

Have a read of a thread I posted last week - I found somewhere that sells 5 star petrol - 102 octane

The higher the octane level the less chance there is of det, meaning you can advance the timing a little for more power

Turbo'd cars will benifit a lot more from a higher octane fuel, but go to high, and you will get cold starting problems as your plugs will coke up as it will burn to cool

PS That 102 octane stuff is a leaded fuel, and if you have a CAT will be of no use to you. The lead will break the CAT down and its efficiency will suffer

can i run that 102 octane stuff in mine stu ??

As long as you have a decat, or dont mind messing up your cat

fully decatted , im off to find me some super rich petrol

Yes. When I had my Calibra turbo and my Evo, when I used Optimax and 2 tins of octane boost I suffered from a misfire. The Optimax and 1 tin of boost worked very well though