I have a Vectra SuperTouring! Ha ha! The wheels are fairly rare now, only 500 sets were ever produced by Irmscher, so people are trying to get there hand on them now to replace damaged ones etc. They still go for fairly cheap though, even with being so rare.
Can you not use a PCD adapter kit to change the PCD of your hubs? Also the offset will be around 10 above the VW offset (think the wheels are et45), so you might need to buy some spacers to make them pertrude more away from the hub (so they don't catch the shocks)?