The Black Ice2 was simply a double-length Black Ice. Look at this article (take the Black Ice1 numbers and just double them):
http://www.overclockers.com/articles481/index04.asp
"Fairly good cooling in a compact package, but the unit's high flow resistance (pressure drop) must be addressed during the pump selection. The new version being twice as large should be about equal to a typical heater core, but with much much higher coolant flow resistance. "
I would also try and fit a heatercore or if space is an issue then go with a Black Ice Extreme.
If your goal is 2 quiet fans and a reasonably small footprint, try Becoolings 12x5:
http://becooling.safeshopper.com/17/48.htm?525
For relatively low flow rate, low noise systems it is an excellent choice (double the 5x5 numbers at the overclockers article). In fact, it looks like the Becooling rad should outperform the BI2 with quiet fans.