Kempower are located north of Brussels. See their website: www.kempower.be
435Nm, that's some meaty torque you're getting! Kempower are very professional and have done literally hundreds of BMW diesels with no problems. Touch wood, I had my 330d remapped in September and have had no worries at all, despite really using all the 615Nm I have on a regular basis.
Interesting remark about the fuel. Must try that
I wonder who'll be the first to reach 1000Nm in a diesel BMW