I know this is a little late, but I had the the dreaded leak too but opted to use the bimmerfix kit to do the fix. So far I am happy with the fix, no leaks after about 500 miles, but I am still checking everyday for a leak. I've done this repair on my brother's 7 series using AGA. It still is holding up coming up on 2 years, but it was WAY more labor intensive.
The only gripe I have about the bimmerfix kit is its price. There is really only about $30 dollars worth of materials in there, however, I do have to say that paying for it is a better deal than the hassle of doing so much labor.

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2006 X5 4.4i