944 Man wrote:
Slender spacers will probably have been used for clearance on the front Boxster wheels. You can keep them (as the front 7" Fuchs wheels are too inset anyway) if you wish and I probably would providing that there is enough stud left for the nut to grip safely (this could be marginal - you need 7mm spacers from memory, but there is only enough stud for 4mm-5mm). If you don't, then make sure that the spacer is off on both sides as they can stick to the wheels or the hubs.
Thanks for the info above 944 Man, really you already answered my question about whether spacers would be needed with the different offsets.
Interestingly though it turned out that the neither front or rears had spacers to fit. I'm not sure they are genuine Porsche, if that makes any difference. Although they are too dirty at the moment to see many markings on the inside.
The club sport wheels went on fine without spacers and look great to me. I wonder if the wider front tyre (225/55) has something to do with it. Anyway the car now looks a bit more how it was intended but with the wider back wheel (which is what I was looking to achieve). And it is handling better, smoother ride and not tram-lining like it seemed to with the other wheels on.