I am planning a Boxster based build also and have been struggling with the wheel spacer issue. Have you given that any thought? I have considered negative offset wheels which I dont think look right and I also have considered lengthening the control arms. I would like to avoid the spacers if possible because of the quality of the ride, the look, and the wear and tear on the bearings. Have you run into any other fitment issues with the body on the chassis?