A few of my friends have the BMS WW and the Coolingmist kits and they have always had some sort of issues with them. They are always fighting flow problems it seems. I went with the Aquamist HFS4 and a trunk mounted Howerton tank for peace of mind for this exact reason. Got it through PTF, Dzenno installed it for me and pro tuned the car and I have never looked back. I love my HFS4 and Home Depot methanol.
'07 335i E90 - PTF ProTUNED by Dzenno - COBB FMIC - AFE DCI - AA DPs - HFS4 Meth
'09 M3 - Stock