I bought a new Defy 1 3 weeks ago and am very happy with it. However, coming for a bike with hydraulic disc brakes, I've found the rim brakes on the Defy a bit...erm..weak. I realise this is only to be expected but wondered if I'd notice any improvement upgrading the tektro to 105 calipers (or even ultegra) or would this simply be relieving my slightly obsessive need to have a full 105 groupset?