I am running the DD Audio VO 6.5's in the front on a 12 RG. Running them off a Micro 4 that is bridged and they are clear up into the higher speeds while battling a FatCat exhaust.
I believe the CX series get used for the tour pak as the VO's are too deep.
The VO's are great speakers. I've heard good things about the DS18 brand as well.