X250.5 vs X250.8

Has any one compared these two amps. Also has anyone compared the X1 preamp with the X22 preamp? I have an X1 and an X250.5 and they do sound quite nice with my Hales T5’s but I’m wondering what about the newer Pass Labs gear? My 16+ year old amp and preamp sound good but will the new stuff be that much nicer?  I recently upgraded my dac from a Perfectwave Mk2 to a Directstream and the improvement is obvious and dramatic. Any advice would be appreciated.