be your best choice. You said the car would be used primarily for autocross and only the occasional 1/4 mile. I'm going to go out on a limb here an say that Z_Shotta has never autocrossed. Take a look at his past post history. Most of it has been deleted because he appears to be a moron. His comments are a regurgitation of a conversation he probably had with Greg about his own choice in the SZ 90 kit. In autocross you want no lag at all. The courses are too tight for you to be waiting for your turbos to come alive. I have the Z1 GT675 kit and can tell you that they are not a good autocross turbo. On a spread out road course with sweeping turns and longer straights...it's a different story. The 530's with MS manifolds spool ridiculously quick and will get you out of the tight turns and down the small straights on an autocross course. They will create more power than you will probably be able to use on an autocross course.
