problem is, it can't me made federally "legal".
here is a list of "nonconforming" cars eligible for conversion. No supras on the list.
http://204.68.195.250/cars/RULES/IMPORT/elig060109.pdf
So you will have to do this by scratch...
Step 1, have an RI submit paperwork for FMVSS compliance procedures, along with crash tests (typically 2) that they have performed on modified JDM supras. Submit request for admitance to NHSTA eligibility list. Get listed in federal register for comment period. This should take 6 months. yes, you will need to crash test 2 Supras. If approved, you will have to export your supra, and reimport it with the conformance bond, HS-7 properly filled out and letter allowing it to be modified. The RI will then have to perform the FMVSS compliance work.
Once the RI is done with the car, it will have to go to an ICI for emissions compliance and testing. Once the EPA and NHSTA approve your paperwork, they will release your bond, and your vehicle. Shouldn't take more than a year or 2.
don't forget, you need to import those 2 supras to crash test first
.