I purchased a rebuilt vf39 from six star and am very pleased with their service as well as the turbo. I must say Jonathan was very informative and went out of his way to answer all my questions and concerns. He is top notch.
As for the turbo, it is performing quite well. My car came with a td04 and it has had a vf23 as well. The vf39 with the billet wheel likely hits boost similar to the stock vf39 but I would think is more efficient, can hit higher boost, and can hold it better up top. They rate it at 41lbs. which is about 15% over stock. For those of you wanting to stay with the vf series or merely want to stay with stock injector their upgraded turbo is the way to go.