I've ran ET Streets in the 26x11.5x16, 27x10.5x16, and 28x11.5x16 sizes with no problems(the 28x11.5x16 is the one I'm planning on sticking with next year). I've also run the Hoosier 28x10x16 slick, which needed just a little banging in the front part of the wheelwell.
Keep in mind the ET Streets are smaller than the size thats written on them, for example the 27x10.5x16 and 28x11.5x16 both have a tread width of only 8.7" while the 26x11.5x16 has a tread width of 9.7". The 28x12.5x16 has a tread width of 10.0" and is one I'm considering going to if the 28x11.5x16 turns out to be inconsistant. The hoosier slicks on the other hand are true to what they claim(28x10x16 = 10" width).
HTH,
Steve