Like some of the previous posters said.... buy the newest, lowest mileage S2k that you can buy with what you have to spend. Make sure you test drive whatever you see.
The AP1 and AP2 issue has been debated to death and beyond. Honda is a careful, conservative manufacturer, and does not upgrade things unless it really needs to - draw your own conclusions from this statement.
And when you are in your s2k, just revel in the fact that you are driving in the finest, lightest, funnest piece of automotive machinery for the dollar you have spent - it will "stir your soul", just as its designer intended!