Many people do it. It sounds great outside the car. Not so great inside the car. On the highway, you will probably experience unwanted sound and drone.
As long as you are not stuck in long periods of sitting in traffic, fumes are normally not an issue.
One suggestion I would make if you are going to try it. Use band clamps. Do not weld or use U-clamps as that is a permanent solution. So if you go to add tailpipes later, there is a slim chance they will fit properly.
With band clamps, later if you decide to add tailpipes, you can take everything apart and put it back together for a good fit.
