Well, they will cost you $65, and they are really great. Nobody can tell you if they will be the perfect iem for you, so at some point you just have to take your chances. But based on the overwhelming positive feedback, you can feel fairly safe about starting your collection and getting them lol.
As far as driver flex is concerned, I have it to varying degrees with various iems. The worst is with the R1's - somewhat irritating crackling. The next worst is the VSD1 - the right driver stops producing sound, so I have to adjust it a bit to get sound coming out again. I hear it slightly with my H-200's sometimes - a very like crinkling noise when manhandling the one of the drivers in my ear (but it happens rarely when adjusting it, and when it does happen, it's barely noticeable to me so inconsequential). I don't get any with my Bassos though (maybe it's because the R1/M6 bi flanged tips reduce it). I think it has a lot to do with your ear canal size and shape, and the tips used, and the iems, and your tolerance.
In summary: do NOT hold back on getting the Bassos due to fear of driver flex, that's for sure.