what is the factory wheel offset for 17" aluminum? I know the bolt pattern is 5 / 108 mm but what is the offset? 35, 40 0r 45 mm ?

Why not check on a website like discounttiredirect.com

The offsets are different for different wheels. The 17" Canistos (stock on the 01,02 etc. C70's) that I put on my S60 have an offset of 43mm. I would think that most of the recent wheels for the FWD/AWD cars are going to be in that 40 - 45mm range. So, to answer your question, there isn't one offset. It should be stamped on the back side of the wheel.

I have to say this. Why are people responding to a thread created in 2006? While the info might be helpful to others thinking of asking the same question to OP of the thread is more then likely not on this forum anymore.