Toro Rosso was purchased from Minardi and made its competitive debut in 2006. It managed 1 point in the season thanks to Liuzzi, which leapfrogged it above Toyota and Super Aguri in the Constructors Championship.
In 2007 the team ditched American Scott Speed in favour of a little known German driver, Sebastian Vettel, who rewarded the team with a 4th place finish (5 points) in China to complement Liuzzi's 6th Place (3 points). The team could have scored more points but Vettel crashed into the back of the Red bull of Webber in the Japanese Downpour and lost the team the opportunity of their first podium finish. This gave them a final position in the championship above Honda, Super Aguri and Spyker and of course above McLaren who were excluded from the Constructor's that year (Spygate).
In 2008 Vettel showed both his talent and the potential of the Toro Rosso. The team beat its sister, Red Bull Racing, thanks to the abilities of the German. He brought it the Team's first and only win and gave them an impressive haul of 35 points in comparison with Bourdais who got only 4. He achieved 9 points finishes in 2008 our of 12 finishes with 6 retirements. The team were moving onward and upward as per the wishes of Paul Stoddart (Minardi Owner) when he sold the team to Red Bull.
2009 saw Vettel moved to Red Bull and Bourdais lost his seat to Jaime Alguersuari mid season, with Sebastian Buemi taking over from Vettel. The season served to highlight Vettel's driving abilities as the team slid back down the pecking order to finish 10th, and last, on 8 points.
2010 saw the introduction of HRT, Virgin (Marussia), and Lotus (Caterham) and the Toro Rosso placing above these three new teams flattered to deceive. Effectively, given the fact that the three new teams were massively slow in comparison, Toro Rosso came 9th and last of the established teams with a combined points haul of 13 from Buemi and Alguersuari.
2011 saw the team finish above Williams, who had suffered their worst ever season with just two points finishes, and the three backmarker teams but saw the team bag their biggest points total of 41, thanks to the 1st to 10th points scoring introduced in 2010. Alguersuari and Buemi were difficult to separate with the former scoring 26 and the latter 15. Over the course of the season their racing abilities were about even.
For the current season, 2012, Toro Rosso ditched their two drivers, holding onto Buemi as test driver. They took on Jean Eric Vergne (French) and Daniel Ricciardo (Aus). After 6 races the results are no better than last years. Certainly neither of the new drivers has so far shown any particular skill which would identify them as future Red Bull material. It's worth waiting for mid-season to evaluate the drivers' potential however the car looks to remain locked in last place ahead of the three teams who I have earlier assessed as being worthy of expulsion.
So - The assessment is that, apart from the Vettel performances of 2007 & 2008 Toro Rosso is a failed team incapable of moving off the bottom of the leaderboard. It certainly had the potential to move forward however, perhaps all of the money has been focussed on Red Bull Racing while they are getting by on a shoestring budget. The drivers, other than Vettel, have shown no great ability to outperform the car and perhaps that indicates the car is the weakness in the team.
If we should expel the HRT, Caterham, & Marussia teams then we should look closely at Toro Rosso and see if it has any chance to redeem itself in its current guise. Perhaps it needs the focus of a new owner who would only be interested in this team. It seems that Red Bull have too many fingers in too many pies to concentrate on moving Toro Rosso forward.
VERDICT: Must pull their Socks up or Sell up