i have a 2 month old nova max .12 turbo and it is very SLOW (it wasnt at the start)i think this is due to running the engine too lean and i fear i have done some damage to it because i cannot belive these engines are that slow! Does it need repolishing or how can i check for damage?

Check the compression.
Take out the piston and liner. Determine how far you can push the piston up the liner. i.e. can you push it above the top of the liner? If so, I'm afraid it's a gonner.