What matters is the voltage the modules run at needs to be the same, you don't mix 1.65v with 1.90v modules, but as long as the voltage is the same, the timings will need to be manually set to the most relaxed settings.
The G.Skill is 1.6V and the OCZ 1.65V... I'm sure I can run the G.Skill's at 1.65v? I purchased the G.Skills during BF for around $73 (after cashback) and I managed to get the OCZ for $34 (after cashback and 2 rebates)... I don't mind running both at 8-8-8-24 CAS8, although I might be able to OC them both to run at 7-7-7-24 (CAS 8)