Waiting for the ultra-d (to do the sli mod)

I've got a pair of ADATA DDR500 on my UT 250Gb, so I'm going to sell them and buy a pair of OCZ but don't know wich ones

1024MB 2x512 Kit Rev.2 OCZ4001024 ELDCPER2-K 284,00 €

or

1024MB 2x512 Kit Voltage eXtreme 263,00 €