When I was time attacking this stage I used the same glitch everybody uses, but I've noticed something I think you don't know about. If you jump on the MM portal, eggman will be transported faster than normal, it saves a good amount of time, if you watch yoshifan's mission 3 video you'll notice his jump, he jumps on the portal, but you need to jump and let eggman fall down in the portal, this way he'll enter in the portal faster, hope I've helped ^_^, if someone don't get the trick I'll make a video of it later. See ya'll o/