Shogun
Prior to 2009 I think it was the STR was essentially a Red Bull chassis designed by Newey and one step behind which was used to great effect in 2008
Since then all teams entering the F1 world championship must design their own chassis. This ruling basically eliminated any chance of Pro Drive joining F1 because they were planning to use a Mclaren chassis. The daft thing was they were accepted as an entry in 2008 but were subsequently vetoed on the basis they wanted to use a Mclaren chassis
Also previously the funding has changed for the teams and it appears more and more resources has been put into Red Bull and taken away from Toro Rosso
Red Bull are based in Milton Keynes, UK and Toro Rosso in Faenza, italy - the old Minardi factoru
As you can see they have different approaches to the low nose concept this year