2 1/4" exhaust or bigger will wear on your wires and plugs?
I dont understand.
Id say closer to 2.5" exhaust piping to support 220whp.
As far as headers go, SMSP,RMF,Hytech,Rage all come to mind when I hear about a potent high hp all motor setup.
The USDM ITR exhaust manifold is cast iron I believe, while the JDM 98+ get a better flowing 4-1 tubular header, not cast...Im not sure if a JDM ITR header will flow enough for 220 whp, (might be a little restrictive)...