Okay I know that people say the things that come with 5in exhaust are a deeper sound and maybe some lower egts. I have a 05 that is will over the 600hp range and im wanting to get rid of my stack that I have now. all the piping on that is 4 in and im wanting to get the egts down some. this may be a stupid question but if I order a new 5in system and keep my 4in down pipe will the 5in have any effect besides sound? or will it help lower my egts at all. I don't feel like trying to cram a 5in downpipe up in there with everything else already there.