I've lost track (reading other thread updates til just now), but is the point in contention about correlation between tea party affiliation or identification and current/former republican party registration, and party lines voting trends amongst republicans? Because the tea party is not an official election registered party, unlike the greens or libertarians. Pretty sure nearly 85+% of tea party movement self-identified people are either formerly or currently registered republicans. Amongst elected democrats in Congress, I don't think there is a single one who also identifies as a tea party affiliate.
Both democratic and republican parties in Congress are documented as being quite polarized, more so than in a century, and it has been in many news reports of statistical studies of congressional voting records that yes, republican congressmen vote pretty much as a bloc especially on party platform agenda items like taxation, health care reform, and military funding. Not so much polarity on mundane technical bills. There are a few notable exceptions to republican platform bloc voting, Olympia Snowe for one, but these excepted reps and sens are the ones that are branded RINO by tea party loudmouths.