I know there are lots of guys running 18" wheels on their S2ks. I would prefer to buy a set of 17" AP2V1s, but I found a set of 18" that look like they would work:
Front: 18"x7.5". Cast aluminum-alloy. Bolt pattern 5x114.3 Offset +45
Tires: Bridgestone Potenza RE050A P225/50R18 95W
Rear: 18"x8.5". Cast aluminum-alloy. Bolt pattern 5x114.3 Offset +50
Tires: Bridgestone Potenza RE050A P245/45R18 96W
BUT I do not want to do anything to OE fenders. I know there are lots of opinions, but anybody care to make an informed guess as to whether or not these would work. I'm OK with spacers if necessary. Thanks.

 

Not even close to the right tire/wheel specs for a stock S2000. Pass on them.

 

Tire specs are completely wrong.

The wheel specs might work at stock ride height but if you want to lower the car at all the fronts would likely need a roll.

Spacers will only make things worse.

 

I know that the front offsets are 7" wide +55 offset and the rear 8.5" wide and offset +65, but I would be keeping stock ride height.

 

v1s

 

Yeah the OEM Ap2 wheels will fit better, look better at stock height and tires will be less expensive than 18's.

 

Wheel specs are fine, tire specs are not. For no fender modification, you would need to run a 215/40/18 on the 18x7.5+45, and a 245/35/18 on the 18x8.5+50.
The tires on those wheels are 2 series higher in aspect ratio than the vehicle is intended to use. The overall diameter of the tire is too large. Speedometer would be off, car would be noticeably higher off the ground, and the higher sidewall would increase the potential of impacting the fender during compression- even at stock height.

 

False. You will damage your fenders if you run into any sort of compression with your wheels turned.

If you run sticky summer rubber and do spirited driving with cambered roads, you will likely compress your OEM suspension enough while the wheels are turned and damage those fenders with those specs. Going up driveways with the wheels turned will also be risky.

Those specs absolutely need a roll up front.

FWIW, i got stock OEM AP2v2s with 2.5 degrees of camber to rub on the fender liner while driving on track.

 

And concerning the spacer comment- running spacers would be the opposite of what you would want to do. 7.5+45 & 8.5+50 are practically flush with the factory fenders, spacers would relocate those wheels outside of the fender line, requiring pulling/rolling/flaring based on spacer width. Spacers are used to decrease offset, so they make a higher offset wheel lower. That is why spacers are often used on oem wheels.

 

I did a few years of autoX, several trips to the tail of the dragon, and several track events, plus years of driving with 17x8+48 with a 225/40 tire with no fender contact (lowered, running -2 camber). That wheel setup is more aggressive (less clearance) than a 7.5+45 with a 215. That wheel size has decades of successful, no fender mod fitment. Was the original Volk s2000 wheel spec.
what tire size are you running on the ap2v2?