[quote="marlin758"]
I bought a CR-Tech box off ebay for £78 - just checked but they don't seem to be listed for the X5 at the moment
When I fitted it I was very impressed , much smoother and more responsive. I think you quickly get used to the extra performance though, it wasn't slow before !
I have just returned from a trip towing a fairly heavy caravan and whereas before I fitted the chip it would be showing 24 .6 mpg it is now showing 29.6 mpg so I am impressed with that

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You will need to check the mpg by doing a full tank to tank fill
As boxes raise up the fuel pressure
The mpg readings can go out the window