Fuel...
You could open a huge can of worms with this question with these forums, however I would suggest any major brand are good quality fuels.
You cannot go wrong with brands such as OD, Byron GenII, Nitrotane, Blue Thunder and such. You get 10 responses and you will most likely get 5 different opinions about the best fuel. Pick a brand, learn to tune your engine with that brand and stick with it... I personally use Byron Gen II at the moment, but have had really good luck with OD, Nitrotane, Werks & Trinity Platinum. They all tune a bit different and when you switch you have to retune your engine so that is why find one you like and stick to it.
Hope this helps a little