You can spend as little as £33 on a 24" bar, advertised as a CREE bar.this really is a minefield, there's quite a lot of outlets selling these on eBay, anyithing from £60 to £200, but most of them are unbranded. I'm going to give s mate a call who fitted a couple to his trialler 90, I'm sure he said his was about £500 though
I am tempted to try one, when the keeper of the purse strings allows. It's relatively easy to tell if it has genuine CREE emitters, by taking a look when it arrives.