While researching the suspension found on the GTO I came across this (I apologize for the size, it's about all one can find on this deal):
The GTO is based off the Holden Monaro, which utilizes GM's Omega B chassis:
http://en.wikipedia.org/wiki/Holden_...2.80.932005.29
Holden Special Vehicles (HSV) built a 427 version around 2002 that changed the front suspension from strut to double a-arms. Only two were built. . .one has sold a couple of times for stupid money, while the other is held by Holden.
Though it would be rather expensive to replicate it is interesting to see the a-arm and "standard" coil over design.