Drilling the existing CDV is a third option. Connecting the two lines (before and after the CDV) might put stress on them and have them break; additionally if your car is still under warranty they can blame the absence of the CDV to deny the repair. Drilling would be problematic because the holes size is not standard (the bit would either be too small or too big) and you might leave residues behind.
I bought the one from
Zeckhausen