it's "span", just so you know.
As far as lifespan, it varies. There are a few that I know of that are well above 300,000 miles. There's a very large number that are over 200,000 now. And probably half of the SR20 motors in this country are over 100,000 by now.
The SR20 is a pretty stout motor, it can take a lot of abuse. Just do regular maintenance and don't let it run low on oil at all and it should last a good long time, even with mods.