This has all been done before.
To say that today Touring cars are the same as the HPI PRO/PRO2 even the PRO3
If you had compared todays cars with the early Yokomos like the YR-4SP or Schumacher SST99 then maybe, but right now their are no "new" cars running saddle packs alla the PRO/PRO 2 and as far as the PRO3 goes it's more simular to the JRXS-R that anything.
If you had done a search you would have seen this "design a new chassis exersize" has been done more time than i can remember.