a +25 offset will bring the front wheels in line with the guards. a +25 offset on the rears seem to scrub even with the guards rolled. i am using tein coilovers though, but i dont see how that would make a lot of difference. if you go a +15 that will stick out a further 10mm past the guards. the closer the number to zero the more the wheel will stick out from the center. the higher the number, the closer the wheel will sit to the car. Having said that, you can move the wheel out with spacers etc to achieve a desired offset. if you get a big offset, ie closer to zero, you cant move the wheel in, your offset is fixed.