One other thing I will add, that's worth thinking about IMO: your Sirrus is a hybrid frame, so aside from any brake/type/mount issues that might be present in converting to a road group, the fit of a hybrid frame is quite different than a road frame. The idea of plugging in a road group on hybrid or mountain frames sometimes works out, but more often than not the frame dimensions are too far from ideal to make it worthwhile. Example: a good fit for me on a road frame will have an effective top tube length of 54-54.5 cm. A good fit for me on an XC mountain bike, effective top tube length: 58.5-59 cm. So, not even close to the same....... Bottom line: hybrids and mountain frames have different dimensions than road frames, to fit the same person. Just keep this in mind.