Well, I don't recall exactly how similar the dash is to a VW Polo, but for me the (original) tuner module fit off to the side, right next to the DIN sized space. Not sure if a pca tuner would fit there though, as it's, IIRC, somewhat taller than the original... There was no chance at all to fit it directly behind the HU, so use of the extension harness was required.

/Michael