Custom Exhaust Pipe tubing for P10

I am planning on doing custom 2" or 2 1/4" custom exhaust piping within the next 30-45 days on my '96 G20.

The question I have is what is the standard life span of heavy gauge piping compared to stainless steel piping. I would like something that lasts at least 5+ years so that I will not have to worry about rust and corrosion.

I am trying to keep costs low, so I am trying to find the most cost effective piping that also has a decenet life span.

Any opinions, thoughts, ideas are more than welcome.

Thanks!