02 and 05 S2000 wheels spec
 

Can anyone tell me the spec of the stock wheels for AP1 and AP2 (width and off set for front and rear)? I am thinking to use 245 45 16" in the front (same size as the rear). Is it possible without rubbing anything!

First, this belongs in the wheel/tire forum.

You should only use a front rim on the front of the S2000. To fit a 245 tire, you would have to use a rear rim and this rim has a smaller center hole than the front rim, so it will not go on the front. If you put a 245 tire on a 6.5" OEM 16" rim, the tire will be stressed beyond it's reasonable tolerance. A 225 tire has been commonly mounted on the front of an S2000 using a 7.5" X 17" rim. Even this will hit the underside of the wheel well splach shield on severe suspension compression. A 245 tire up front would be rediculous unless you get a wide body kit and custom rims and even then, you will most likely rub badly when the wheel is fully cranked.

Moving to wheel/tire forum

since we are on the subject of stock wheels, what are the offset's for the AP2 front and rears? and if we get diff wheels with same specs will they fit no problem?

I can't quite recall the exact numbers for the OEM 17" rim offsets. They are about 55 front and 65 rear.
I'm not sure what it is you're asking. If you get ANY rim that is of the exact same specs, then of course they'll fit. The "specs" being diameter, width, offset, bolt pattern and back spacing.