the ultegra cranks should work. the rings may have to be replaced due to chain line. if your chainline is straight it should be no problem. but road chainrings (not singlespeed/fixie) have pins and ramps for shifting. if the chainline is not completely straight your chain may slip off at times. which is not good.but also if you're using a 9 speed or 10 speed chainring, which is what will come stock on new ones, the ring will be skinnier than a 3/32 even, so your chain will do some clanking around. so yes you can use the stock ring, but i would at least save money for a new ring in the near future. so in this case i would recomend a cartridge BB because they have adjustment to them. so you can get your chainline really straight. unless it is way off to begin with. but that shouldnt be the case. the new ultegra cranks are the shimano octalink set up, so you NEED a shimano octalink BB. i think the ultegra 68x109.5 should fit. but it is cartridge, so it has adjustment to it if need be. it's english threaded, but they have italian too if you need that. im taking it you know how to install/take off cranks, and BB. make sure you have the proper tools, you can cause much distress if you go into it with some vise grips and a screw driver. anyways, i hope this helps, im sure others can expand on this if i left anything out, or messed anything up. good luck, and have fun