Just curious, between a C2S and a C4S, do the same factory wheels (example, stock 19") come in different offsets for either car or are they the same?

 

C2 is a "narrow body" while the C4 is a "wide body" - I think 44mm wider - therefore to get the rear wheels to fit properly they use rear wheels with a different offset. Typical Porsche C2 rear offset is 67mm while for the C4 the typical rear offset is 51mm.

 

yeah i think all the wheels come in different offsets (for the rears) except the sport (grey 10 spoke) ones, they use spacers with those.

 

Does the larger offset number mean the wheels will stick out more (wider track) or stick out less?

 

I think if the overall width of the wheel is the same, then it's actually the other way around. The lower the offset number, the farther the wheel will extend. If you are going to a wider wheel, then the wheel would extend even farther. This might help...

http://www.1010tires.com/WheelOffsetCalculator.asp