Help!

I've a tire/rim problem and I've been told different things. I have a set of Advan Kreuzer 5 in 225x40x18, +45 offset, I've noticed that the steering wheel shakes when i'm driving about 80 or above. If I put the stock rims on they wheel doesn't shake and its fine. Some shops have told me that its the balancing and some have told me my rims might be warped. Any suggestions?
Does anyone else have this problem? with the same set-up?

Thanks

 

Bring it in to have the tires rebalanced