If you are serious about top end power, the Stage 5 will definitely give it to you. It will be a lazy bitch off boost though. I have a 60-1/stage 3 setup on my 2.3 Mustang, and I don't get ANY boost until 3k rpm. Full boost by about 3600rpm. It will be worse with the stage 5, especially with less displacement. What is your HP goal?