tire spec questions
 

how come stock s2000 uses 215/45/17 245/40/17

why did honda make the front tires 45 not 40 or the rear tires 45 like the front

i wana get some rpf1 17x9 +45

should i do 255/45/17 all around or should i set it up like honda where the front tire is slightly thicker like F 255/45/17 R 255/40/17

what are the pros and cons to this

You clearly don't understand how the numbers on tire sizes work. The 45 or 40 is a percentage of the first number. This explains it nicely. How to Read Tire Sizes | Goodyear Auto Service Center

Now if you are doing the same width tire all around and want 255's the correct size is 255/40/17. Using a 255/45/17 would mean the tire is taller than stock which can affect handling, your speedo, and fitment on the car.

The OEM spec tires are all the same outside diameter, the part that touches the road. This simplifies stuff like traction and stability control as well as anti-lock brakes.

-- Chuck

... therefore for the front tires to have same outer dimension as rears, for both ends to have the same height of rubber from rim to road, the profile number, the 45 or 40 in the size, are different because its a ratio of the width, and on our cars rear tires are wider.

So even though one is 40 and the other 45, these differing numbers represent the same amount of rubber from rim to road.

Can I run a 17x9 inch wheel all around +45 off set with no rubbing I have extra wide front fenders

Maybe but I'm thinking "not." But why? Tire stagger is part of controlling oversteer on this car. Too much front tire will disrupt the handling.

MY00 to MY03 ("AP1")
Front:
16" x 6.5", +55 offset, 205 tire
Rear:
16" x 7.5", +65 offset, 225 tire

and the OEM MY04+ (AP2) wheels are as follows:
Front:
17" x 7.0", +55 offset, 215 tire
Rear:
17" x 8.5", +65 offset, 245 tire

-- Chuck

The big wing I am Gona pit in the back is Gona solve that problem

So race car. Much fast. Wow vtec.

Double stack??

At what speed do you think that big wang is gonna really start showing a difference? What about low speed corners?