Nice bike, a Cube fan myself (AMS 29er) I would ride it as it mate, your not going to make that much difference with out spending load of cash on it. Some light tubes will help a bit but tyre choice will make the biggest difference. Have a look at lighter tyres as well tubes and maybe look for something a bit skinnier but your still looking at around £60 - 80 for some top end stuff.
let us know how you get on with it.
let us know how you get on with it.