I personally think, if you're putting No2 on something, you should be prepared for some extra maintenance. If that means getting the blower rebuilt after 50,000 miles or something, that's what you should expect.
Some people run it on cars for years with no issues, some blow their engine in 5 weeks. If you're gonna do it, just make sure you do it right, or make sure you understand that you'll be replacing some expensive items later. If you use a direct port system, which will cost a ton, the only thing you have to worry about is the engine internals. You have to worry about them anyway, and with no other mods a 50-75 shot should be taken in stride. Assuming the strenth of our internals is what we've come to understand they are, and that the A/F ratios are within safe levels. A small level of gas like that should be no problem. Like anything else though, it costs a little bit to have it done the right (safe) way.