Doing a barrel change is easily do-able.....for pistolsmiths with the correct tooling and knowledge to do it RIGHT.
You will have to be sure to get a barrel of the same vintage, since S&W has made some changes to the barrels over the years.
One way to get the right barrel, and get it installed PROPERLY, would be to send your gun in to S&W and let the experts do the job.
In the long run, this will usually cost less, and will have less aggravation with getting the wrong barrel, or a defective barrel, Etc.