Maybe post your Q over here in the RIMS thread?
http://www.aussiehomebrewer.com/forum/inde...56974&st=60
Or maybe better on the brown pumps thread here:
http://www.aussiehomebrewer.com/forum/inde...showtopic=59811
Can't comment myself as I use a march pump.
I have no issues an Ebay-sourced 12V little-brown-pump and my HERMS coil.
I assume that the resistance from 6m of 12mm tube is much greater than what you'd expect from a RIMS tube.
There are a couple of videos showing it in use on my Blog post here.
However, the flow rate is not that high (about 3l/min) which means that the grain-bed-temperature lags behind the HERMS-measured-temperature more than I suspect would be 'ideal' if a more expensive high flow pump was used.