this is what the dealership is trying to convince me of, a new chain is a must... if this is the case what chain do you recommend?

A new chain is a must?  Baloney, unless you need a new chain anyway.  (How many miles on your current one?)

As far as recommendations, you can try various searches for chain info.  But my (Feb 2004) Chains & Sprockets page will give you some idea of what's out there.

that is BS dont buy a new chain you dont need it. You dont even need one for a 14t sprocket. I have both on the stock chain.

For maximum chain life both sprockets and the chain should be replaced at the same time.  If both your spockets are in good shape and your chain has low milage - go ahead ands just replace the one.  If your chain is wearing, an old chain/new sprocket will result in dead chain/dead sprocket in short order.

my bike just got over 6200km....

i thought he was bullshitting...thanks for the info!

Your chain/sprockets are barely broken in.  If you've been keeping them lubricated every 1000-1500 km like everyone should, then you can expect to get 24,000 km from the set.

Re-use everything.  

Quote from: mjmFor maximum chain life both sprockets and the chain should be replaced at the same time.  

The front sprocket needs to be replaced but the rear should go 2-3 chains.
I changed my original chain at 18,000 miles and front sprocket at a little over 20,000 miles.  The rear was good as new.  The front had minimal wear.