The IRS (Independent Rear Suspension) is based on a Jaguar V12 XJS.  I have had to modify the spring/shock mounting points to allow a longer unit than standard.  This is because I am using air ride Technologies 7000 Shockwaves.  To get a reasonable amount of travel the unit has to be considerably longer than a non air unit to allow for the seals.

The suspension arms are the standard units, I was hoping to use aftermarket tubular arms but because of the geometry it was not possible.  The driveshaft's are modified (Hex Stainless bar) and the hubs are special stainless steel machined items.