Dual exhaust overkill?

[Mistoffeles]

I've been reading the forum a bit and came up with this as a basic plan for what I want to do, as I would rather rebuild the whole exhaust now than fix the bits that need it and have to rebuild anyway next spring.

From the existing headers, 2" pipe to Hi Flow pre-cats, more 2" pipe to Aero AR20 resonators or Thrush glasspacks, then I have to figure how I am going to connect the 2" out to the 2.25" (or larger) on the input end of Thrush Type 304 stainless steel welded mufflers.

Is this overkill, or do I need all of it? Should the resonators go before the pre-cats? I've never done anything like this, the only car I've worked on myself was an X1/9 and not on the exhaust.