hi ,,, i also use utorrent,,, as regards tweeks, there is not much you can do,,, its more to do with your hardware if you want faster and more stable downloads and what profile your broadband is,,, im on an 6meg profile and achive about 5 meg as im about 2km fromthe exchange,,, i use a site called kitz.com in the uk and they sugest useing a router and resetting the MTU (Maximum Transmission Unit )
http://en.wikipedia.org/wiki/Maximum_transmission_unit
if files collide then it has to be sent again,,, if the mtu is set to high it could be to fast and collisions happen and it has to be sent to you again slowing the download,,, default for ethernet setup on a windows os is 1500,,, to high,,, i reset mine to 1423 and torrents take less time now because files dont have to be re sent.
http://www.kitz.co.uk/adsl/index.htm
look in ADSL tab at the top of the page and then "tweeking mtu" ,,,,,,,,,,,,,, good luck