Only thing I question is if you get a TFI or another fuel management, I do not think you need a download. If you change pipes, and air cleaner all you need is a TFI or something similar. You can do a download, but not neccessary. Correct me if I am wrong. I am being told if I add slip on's, no problem stock, but if I add Air Filter as well all I need is a TFI, no download.