I personally don't like the GTX and GTX-R gyros. I don't like how the rubber seals fall off, leaving the bearings exposed (why make a 'sealed' gyro if it becomes unsealed in the first week of use?) and I don't like how the pinch bolts work on them. I'd rather use a normal cheap gyro and Knarps.

however, I don't think normal gyros fit over internal headsets. I could be wrong though...