OK. You are seriously confused, but that is understandable considering the history of the Premiere. There are 5 models of the TiVo Premiere - The original 2-tuner* TiVo Premiere(model TCD746320) and Premiere XL(model TCD758000). The TCD746320 was replaced by the TCD746500, also 2-tuner.
At some point they came out with the 4 digital cable tuner Premiere Elite(model TCD758250) which was later renamed the Premiere XL4 about the time they released the Premiere 4(model TCD750500 ). From the price you are quoting, I am guessing that you are getting the Premiere 4, not the Premiere XL4. BTW, the phrase "standard drive" is meaningless.
I really can't help you there but for anyone to help you, they will need the actual model #. Once again, "standard HD" conveys no information absent a model #.
More correctly, the Premiere XL4 and Premiere 4 have 4 digital cable
tuners. Should work fine on FIOS.
The TiVo stream does not support watching on a TV. It is for converting and transmitting content to portable devices such as an iPad. You need the (AFAICT still unavailable) TiVo Mini.
* maximum of 2 active tuners that is. They actually have 2 OTA digital, 2 cable digital, and 2 analog tuners. Any two of the 6 can be active at any one time.
Note: The difference between the XL(4) and the base models is more than just drive size. Both the XL and XL4 are also THX certified.