Hi All. I've installed 2 1/2" metal studs around the perimeter of my basement and was hoping the unstable feel would go away after my drywall was attached. The drywall is now attached and if I put some wieght into a wall it still has some give to it. Should I be worried about drywall joints cracking with this movement? Thank you!

Get thee to the John Bridge forum (just google it). There are lots of pros over there ready and willing to answer tiling questions. Over here, with the exception of Bill and Mongo (both hang out primarily in the bathrooms forum), you will mostly get answers from hacks.

I don't reccomend sceduled maintainance of sewer line,mechanical or chemical. Without doubt both work but only prolong the misery if indeed there are large roots. Chemicals are also envioromentaly irresponsible. I do have a suggestion that might save money and take maintainance off the table. Since you are digging up part of the line anyhow,get an estimate for "relining"the intire line from house to city. It's a proceecure where each end is dug up and a seamless linner pulled into place effectivly sealing the system.

Usually due to normal settling, but also shows indications of an inexpert dry walling job. Some history might help. How old is the building or is this a recent renovation or addition? How long have the cracks been there? Are the cracks growing? If growing, how fast? Any foundation cracking?