i'm still on the stock turbo and would recommend gutting the UP. it's cheap (free). After reading nagys post i'm wondering what i should do when i get my bigger turbo, but for now it works great.
I for one love working on my car, even if there's no good reason to do so. the whole removal, gutting, install process probably took 5 hours. removal and installation was a pain, but the gutting probably took the longest. I had to drill holes in the cat, punch it out with a screwdriver, then use wire wheels and burrs to get the inside of the pipe perfectly clean. i would also recommend taking out the EGT and plugging the hole with a bolt so that thing doesn't get sucked into your turbo.
i think there's a how-to on gutting somewhere around here.