There is no "standard" version or definition of "far right." The terms
far right and
extreme right merely apply to groups and ideologies that are further to the right of the mainstream center-right. While the term certainly applies to fascism and Naziism, it also applies to those who hold extreme nationalism, chauvinistic, xenophobic, racist and religious fundamentalist views. By far the most prevalent of those political positions in today's America is the religious fundamentalist views of the far right. And it is that very subset of the Republican party's far right that has co-opted the Tea party as their own.
The far right and the Tea Party have become synonymous thanks to the likes of the Sarah Palins, and of the now-former Virginia governor Cuccinelli who's far right religious views on abortion and birth control, typical for most who identify as Tea Partiers, got him voted out. Granted, equating immigration policy to effective pest control didn't really help him, either, but that position on immigration, that of extreme nationalism, is also part and parcel of the Tea party's far right position.
Here's a
NY Times story that tells you right up from that the leaders of the Republican establishment are alarmed by the emergence of far-right Tea Party candidates. The article illustrates quite vividly how the Tea Party has become the far right wing of the Republican Party.
G.O.P. Weighs Limiting Clout of Right Wing