Scott,
With all the additional "volume" you are going to create by lengthening the car you should be able to move the water tank behind the rear wheels and then hang the turbos in that area. You need to hire Jeff Heywood to do the headers and new tank, he did them for Junior and he is one of the best fab guys around. His headers are true works of art and he has done a number of racing turbo header setups, several for Indy cars and has lots of experience getting every thing tucked in.
Rex