I suppose that one will do the job. I bought this one:
Here for sale:
http://www.ebay.de/itm/NEW-PLX-DM-6-52m ... 2a464a8888I think I even got it a bit cheaper, something like 180 euros. It works awesome.
The best would be the lowest position because it senses the fumes from all cylinders. But I couldn't get it in, there is not enough room in the tunnel. That's why mine is at the high position, but now it only checks the inner cylinders. I know not all cylinders get the same fuel mixture due to the difference in intake lengths, but I have to do with it.
Here a few pics of the installation: