millage correction?????

What we need is a test bed with a 2nd hand BECM and an old instrument cluster....

Seems to me that rather than attacking the BECM, all it needs is to look at how the mileage is stored in the instrument cluster. This is obviously adjustable in the sense that it increments. So if you find out the type of storage medium and the method by which it is incremented, it ought to be fairly easy to increment it out of the car at fairly high speed until the max number is reached, I would assume that it would in fact then re-set to zero.