Can't believe this thread is still alive. Well, for what it is worth, I went down this path (modded TD04) years ago...last decade in 2004, lol. Generally speaking, the turbo pulled like a small V8 in the low end...hit about 250wtq very quickly. I was running 21 or so psi in the mid range, which felt great. That said, low end torque is deceptive, making a car feel faster than it is; anybody who has driven a diesel will know what I mean.
At the end of the day, it could not surpass 245-250whp. We are talking with typical stage 4 mods. It held 18-16 or so psi in the 6,000+ range, but power still fell off towards redline (on the dyno, at least, but it felt good). This is on a dyno that put a stock 2.0 at about 170whp.
While a fun and comparatively inexpensive turbo, my advice is to think twice before going this route and make sure it suits your goals. Sure, today there are fancier options to make a tad more power that I did not have back in the day (EWG, E85, headers, good intakes, etc). But, consider how much you are spending to eek every last bit out of a turbo that is small. I do not care what wheel you put in there: the hot and cold sides of the turbo are not changing in size. You might be better off just going bigger from the start. Consider that you constantly hear stories of people going bigger and almost never going smaller...this from a guy who is on his 4th, and largest, turbo set up, lol.
If there was a turbo that made and held 300whp and still made huge torque on a 2.0 below 3,000 rpm, we'd all be running one. Physics is working against us, unfortunately.