Thanks for that info I will take a look into that site
Rob the info you posted was for VR HSV

My god do I have to include Aydiffs as well

heres what I have found so far........
HDT Special Vehicles was a Holden-backed 'hot-up' division founded in 1980 by Peter Brock. Kicking off the line-up was the 1980 VC HDT, complete with flared guards, different wheels, lowered Bilstein suspension and a bit of engine work. Flowing on from the VC was a string of Commodores - the VH Group 1, 2 and 3, ADP Pack, SL/E, HDT Improved, VK SS, SS Group 3, SS Group A, SL Group A, ADP Pack, Calais Director, Berlina and SL, VL Group A and Plus Pack, Sport and LE, Aero, Group 3, Corsa, Director and the Signature Series. There was also one non-Commodore product thrown in - the WB Magnum (which was based on a Statesman).
In 1988, however, things went very sour between HDT (namely, Peter Brock) and Holden. For a number of reasons - most notably the notorious 'polariser' - the partnership dissolved and the HDT name was sold to one Mr Joe Collorafi. Relocating from Melbourne to Sydney, Joe kept up the HDT parts and information supply and released the Series 2 VL Aero, Magnum ute and the Sport. Joe kept things running until the VR era.
In 1994, Len and Sid took up the reins and ensured new versions of the established HDT models - the Aero, Magnum and Sport - were developed for each Commodore model up to present. The VX Aero Signature is their latest release