Well the 3 car method may offer some protection to the team. But from a manufacturers point of view the 3rd car is somewhat of a white elephant. Its not eligible for manufacturers points unless nominated and only 2 works cars can be nominated to score points at any one race weekend.
Vauxhall are a much bigger monster in terms of market share compared to SEAT, and quite understandably SEAT don't want to run a 3rd car if it takes
resources away from the 2 scoring works cars. If a driver brought money to the table then I guess it would be more achievable.
3 cars would be excellent and they have done it in the past with the Toledo's and at selected rounds with the Leon. In 2006 of course Thommo shared the drive with Turner, as Thommo had WTCC commitments with SEAT. So essentially they only ran 2 cars throughout the season, except for the final round when they ran 3 as Spain brought Thommo's WTCC machine to the party.
Though I'd love them to run 3 cars, just because I feel it offers them some security in the race to have another works driver on their side and in the way of the competition.
At some point they are likely to run 3 works cars at one of the rounds in 2009, as that is the prize for the SEAT Cupra champion. I can't see them laying off the 2nd works driver for one weekend to let the SCC champion drive it instead. So 3 cars would be essential, whether its a TDI or a Petrol is anyone's guess at this stage.