It would be far less expensive to get the IRS out of a 03-04 Cobra and modify it to bolt in, which is no big deal. The cars composure would improve dramatically with the IRS too. I miss my 03’ Cobra a lot, I never should have sold it. The IRS was very, very nice. An added bonus of IRS is you don’t need to deal with driveshaft vibrations/harmonics like you do with a solid axle.
I have been wanting to pick one up forever but I am so busy it will be quite a while before something like that happens.
The downside is that if you are making 450rwhp the IRS will need axles, bushings, etc. they already have 3.55’s in them already though which is ice,