Planning on ordering my MK4 kit sometime this year and would like to install a rear IRS. Looks like I could save quite a bit of money if I could find a good salvaged 2015+ Mustang IRS 3.31 Rear End Drop Out. Sounds like if I do this I can use the differential, spindles, hubs, brakes and rotors. Is this correct? The ones I have found for sale are salvaged units that have 10,000 - 20,000 miles on them and far enough away I can't go look at it before buying so have to rely on pictures and description. I've heard sometimes you can find a new drop out but haven't yet. Any tips on what to look for or look out for when searching for one? What would be a good price for one of these salvaged units?