well the problem that i have is that.... my 96 1.8tq came with 557 ecu....And there is not much i can do with tunning it.....There are no chips available for it....The option that i was thinking about was changing the engine wiring harness.. from my car to a later one....Can some one please tell me how possible is it to do and which items eg sensors ill need to change?????

and for what purpose do you need to tune your ecu? i.e turbo upgrade? or just want to bump up the stock turbo boost?

There are a few ecu versions being M, N, P and C.

and they list the 557 for 96-99 which all use the same chip.

connectors at the back of the ECU.....unless i buy same ECU... but i dont see the point of that either....

If you can get me the Bosch#, I can find out if UPsolute have the program for you. It's on the label on the ECU. Bottom left corner right under the word BOSCH. should have something like 0 261 204 ###
give me the last 3 numbers, I can look up for you.

We have programs for the 557 ECU, but to make sure have the one for your specific ECU.

gary