To be honest, why get a 2.0 litre?... go to local dealer and test drive the 1.6 CDRi.., ( in fact test them both out if you can)
Whatever you decide, I am sure both engines will give better performance than a 2.0 litre Carens
The Ceed is a much better vehicle all-round than the Carens by a great margin, (apart from luggage space!)
Check the official emission figures and resulting tax bands(2009) as a final crowd pleaser.
To be honest, I drive a lot of miles and don't feel the need for a larger engine, and my insurance, tax and fuel costs feel better about it too

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All the reviews in the motoring press prefer the 1.6 engine option too.