OK, quick explanation of offset. Your car needs 20-25mm. If you put a wheel on with an offset of 5mm, it would stick way out from the car and probably rub on the fender and maybe even look a little odd. If you put a wheel on with an offset of 40mm, it would go in too far and the tire would rub on the strut on the front and probably rub the trunk/shock mount area on the rear.

Anytime the offset is greater than what you actually need (like with 40mm going onto your car), then you can use a spacer to move the wheel outward to where it should be. To make up the difference, you'd need a 15mm spacer (25+15=40). The spacer basically changes the offset requirement of the car, so with a 15mm spacer, your car now needs a 40mm offset.

A spacer is just a round piece of aluminum with holes drilled to fit the bolt pattern of your car. To use spacers, the wheels must have the same bolt pattern as your car, which is 5x108mm. If the 17" wheels you want to use don't have that bolt pattern (I doubt they do, but check), then you'll need an adapter. An adapter is the same as a spacer, except that it has studs pressed into it for the wheel to bolt to. The holes are drilled to your bolt pattern, and the studs can be placed at almost any bolt pattern, making it possible to bolt on wheels with larger offsets of almost any pattern (sometimes two bolt patterns will overlap, so it's not always possible to use all combinations of patterns). The limitation of this is that the adapter has to be about 23mm thick in order to support the studs. On your car, a 23mm adapter brings the required offset to about 48mm. This might work if you use tires that aren't too wide, like a 205 section width. Often times people will use small spacers (5-10mm) to push the wheels outward and widen the track of the car, which can improve handling. You'll accomplish the same thing with the adapters.

A set of 4 adapters will cost about $250-$300. A set of spacers is much cheaper, HOWEVER, you must use longer wheel studs with spacers as thick as what you'd need, so the cost will be similar. www.wheeladapters.com makes a good product, and I know of at least 4 cars that have used them sucessfully to mount wheels from a FWD Volvo. You'll need to know the bolt pattern of the wheels to buy adapters.

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