It has a 68mm BB shell so you will be able to replace the cranks with pretty much anything as long as you are also willing to replace the bottom bracket. The bars are 22.2mm which is not as common or nice as 31.8mm, so if you replace the bars you may also end up replacing the stem. The wheels, saddle, etc. should be pretty standard. If you have any specific questions about specific parts you should probably ask City Grounds or whoever you are buying the bike from. My guess is that the bike is a pretty good deal for the money.