I have some Reaper X modules. They do not fit in slots that are next to each other and the OCZ website states this. I had to remove the heatsinks in order to get the RAM to fit into my system, as not only did the heatsinks foul each other, they also fouled my TRUE 120.
I am not 100% sure whether Reaper X I G.Skill would work either, as the heatspreaders on the Reaper X modules are very thick. Going just for the G.Skills is a much better choice, as they are cheaper and run cool.