I'll second Smokeysmoo with the economic sense. I think the Sirrus has v-brakes (and multiple gears, not a single speed), so STI shifters won't be compatible (STI shifters have short pull for brakes, though you could use travel agents, but again, more expense and more questions on functionality even so). Even if you don't do STIs, you'll still need: handlebars, tape, cables, shifters/brake levers, possibly new stem, possibly new front derailleur. Add in even more for labour if you aren't comfortable mechanicking that lot and it will really add up!!!
However, if you want a bike with STI, it may still end up being cheaper than buying a new one. And personally, I don't care too much about what the bike looks like so long as it fulfills a function. So to answer your question: yes, absolutely. But it will cost you and you'll have to work out if you are willing to accept that cost.