Yea, after major work there is always a period of wondering what the hell else can/will/might go wrong. After I rebuilt the VR6 in my jetta late last year I went through the same thing. Took about 1k miles (which at the time was about 3 weeks of driving to work) before I felt confident with it. However, I never had the feeling with my Scirocco's. I do all kinds of work to them and never give my work a second thought. It's rather odd now that I think about it.