Thinking about turbo on my/6 again...

I have a cobbled exhaust at this point anyway, put together from scraps out of a dumpster that's next to a local muffler shop. Just solid enough to be able to run it and keep the neighbors quieter than the truck.
For boost quantity I was thinking 6-8 max.
But just like too much cam I don't want a turbo that hits its stride at an rpm higher than I'm thinking I'll ever see this thing run.... I don't want something that will max out at 5500 when I don't think I'll hardly ever see 4k rpm.