Considering Buying TiVo Roamio Pro

I'm considering buying the new TiVo Roamio Pro. I live in Arizona and we have Cox Communications for cable. I just noticed that the DVR that I have with them, is starting to delete recordings after a couple of days and I'm not sure why. I can't seem to find a setting to stop this from doing it automatically. This has never happened before, as I was able to keep things for up to two months or more without messing with a setting.



So this brings me to the new TiVo, I'm wondering if the cable card that goes into the DVR will cause pixelations? I keep hearing this from a friend of mine that works for verizon. Can anyone shed light on this before I make this big purchase. :)