The ACDelco 12595087 Coil Bracket comes with 4 threaded holes that match the thread size of the coil pack bolts. However, the alignment is not the same and will require a min. of two hole drilled and taped. I selected to only mount 2 of the 4 bolts since one could interfere with an existing wiring harness and the my particular selected skewing of the coil pack to the housing leaves the 4th coil pack attachment point without a contact to the bracket.
The initial plans were to relocate the coil pack at the rear of the engine compartment but it was not doable and would not fix any heat issues. Nonetheless, longer wires would still be a key to best relocation options and the plan to only order the 1, 3, 6 wires remained set.
With all parts and car on hand and after careful placement, calculation and reviewing heat/air flows, the skewed mounting of the coil pack to the new bracket; with that now new assembly being mounted close to radiator worked the best.
Others may adjust the mounting based on different country/options/year model. However, the pics below should convey the concept well.
Note: The ACDelco 12595087 Coil Bracket is a thick piece of quality steel that serves quite well as an added "Heat Sink" to the coil pack bottom. It is factory powder coated and should last many years. Living in the tropics with daily temps always above 27C in most locations, will cause constant engine bay elevated temps.
See preparation of ACDelco 12595087 Coil Bracket @
http://s392.photobucket.com/user/Calif-Native-Data/library/Opel%20Omega%20Parts/Opel%20Omega%20B%20Coil%20Pack%20Relocation/Coil%20Pack%20mod%20prep