Don't have the turbo so I just used to glance over the mods but I seem to remember that there was a person/member on PT CREW that used to make and sell all the external pipes in hard form to boost performance. Not sure if he's making them any more. He was called AMX1397.
I would think, if you have the time, you could do some of those modifications yourself by taking out the old flexible pipes and come up with something the same diameter in hard form that would fit your PT or go over to
PTCrew.com - Learn it or Burn it. and search around for hard pipes or AMX1397.