Just a quick question here regarding Catalytic Converters. I am trying to fab one up to replace the resonator on my custom job.

1) Most of the metalic core "high flow" cats typically don't have a heat shield. Should I be concerned with the proximity to the starter?
2) Are there any negative performance effects of running a longer (physical size) converter? I can get either a 9"body or a 12" body for the same price. The advantage of the 12" body is that it length is such that It will fill the space needed without additional welding (Save the flanges) , but the shorter one requires me to lengthen the in/out pipes before welding on flanges.

Don't know about heat, but the larger size should be no problem. The original Fiero CAT was pretty big, but a design that I think is no longer being made.