i have seen insurance companies charge a little extra and even refuse to insure vehicles that have simple mods such as grooved discs.
they look at it in this way "he's put better brakes on, so he's going to drive faster"
also mods, no matter how small tend to stereotype the owner as a Mc Donalds chav racer, the kind of crowd main stream insurance companies want to steer clear of.
best of luck, hopefully you shouldn't get much if at all any price hike, if your insuance company are fair