i did the research a while ago and apparantly civic ek4 vti-r wheels clear the dc2r brake calipers. so 15" wheels are fine.

there are spoon brake conversion parts available which i think eliminates the need to shave or machine the ITR caliper brackets (maybe someone can confirm?). The parts available are 3mm spacers, 4x100 282mm rotors, and longer hub bolts. Maybe some 1 can also confirm if these parts are legal? My knowledge is that spacers are illegal..