I did it myself. Total upgrade cost was about $110, but I was damn thrifty. Competitive had the lever/caliper set on sale for $230 or so and the bleed kit was another 30 bucks or so. They also had a $50 off purchases over $250 promo going at the time, so out of pocket was ~$210. I sold the 105 levers for $100 via Craigslist bringing it down to that $110-ish total.

The install wasn't too hard if you're not mechanically incompetent, but I would recommend splitting it up over a couple days.