nitrous newb

[mtv not bullets]

I'm sure this sort of thing has been asked before, but i haven't found answers to my specific questions by searching, so:

I want to run some nitrous!
This is a stock 91 block with 140,000km (~85,000miles). I heard 91 blocks have forged pistons and are generally good for this sort of thing. But is this a bad idea? Its my daily driver, I don't really want to blow it up. I also don't plan to run a ridiculous amount or do it all the time.

So, whats a safe shot of nitrous for my engine? I've heard both "don't use wet systems, you'll blow up your car" and "don't use dry systems, you'll blow up your car". Which is the better way to go? I'm also interested in some realistic ideas about what kind of power I can make and at what rpm it is safe to use.

Thanks