I'm playing stuff like burgmuller pieces and want to get more expression into my playing-currently have a yamaha portable keyboard which has no sensitivity in the keys.
Moving on, the same thing seems to have happened between the YDP160 and the CLP320 - not sure if it's for the same reasons as the previous product clash. However, whichever you decide on, be it the YDP or the CLP, you will be working with the same GH hammer action. The specs are virtually identical save for the CLP320 having a slightly bulkier casing (I'm talking about cm of difference!), more polyphony and having the "Pure CF Sampling" for tonality which the YDP does not have.
What it really boils down to is whether or not those three difference really make that big a difference to your ear. The YDP160 will be slightly cheaper than the CLP320, being from top end of the entry-level Arius range.