I have an 06' with the Edge ez module, an A. F. E. cold air box and I am wondering what kind of difference in E. G. T. 'S I could expect to drop by adding an aftermarket exhaust system? Also wondering if staying with cat-back is better than turbo back because of inspection/emission issues. What is the top maker ? Magnaflow or M. B. R. P. ? Thanks, Woodpkr