It's a good fit, just designed for standard pipes. I had to dremel and sanding disc the aperture to increase the cut outs. Uses aftermarket fixings (screws) if I remember right as it doesn't have the OE fitting attachments. I'll have a look tomorrow to jog my memory.
Just replaced my splitter this afternoon, has a disagreement with the exit ramp to road of wickes carpark. Took some good chunks out of it. Few pics of the diffuser. It does stick out the back more aggressively and has a better shape and profile. Not sure what other more expensive ones are like but never had an issue with it shifting any.