I recently went through the Chip research for the 94 540iA I have. Last week as a matter of fact. It appears that there are very few actual 540's of this model year that can actually be chipped. They apparently used dozens of ECU's and applied dozens of Software patches in our model year. As a result the chip makers post chips for one particular ECU and software release. The websites for Turner and Enhanced Auto Technology all post the specifics you need. You will have to remove your ECU to get the detail information you will need to order. Good Luck - Johntee540