I have a 01 wide glide with screaming eagle heads, exhaust and not sure what else. I have tried to find out what it means to have these parts...performance wise. But can't find a whole lot...are they really better and if so is it a big performance difference versus stock heads and exhaust? Wondering since I have the heads and exhaust...what else it may have gotten too? Probably a silly question, but would like to know.