115mph is well off the mark. standard the best i ever got was 125, now after a few mods filter, bluefin, cams, full system+ decat its gets just over 130mph........... I am thou now going down the 2.0l blacktop route because to gain anymore power out of my 1.6 its just going to cost big money,
Going down the 2.0 blacktop route sounds like the right idea for you.