Was looking at buying a new one only a few days ago and this is the cheapest place I found selling them:
http://cgi.ebay.com/ebaymotors/Nissa...s#ht_529wt_939
Works out about 230 euro plus postage costs.
I ended up just throwing in a second hand one the other day and that sorted mine out for 80 quid. just hope it lasts!
If you want to test and see what the car would feel like without the vvt just disconnect the solinoid valve and take it for a spin.
I tried it and it didnt make as big a difference as i thought it would but the car felt a bit dead in 5th gear pulling from say 50ish on the motorway and since my car is a road car I didnt want that so decided to keep it.