Thompson is a great driver, one of the best undoubtably of the modern touring car era.
He's currently leading the World Touring Car Championship, if he were to win such a prestigious title.
Would he quit the WTCC to lead a full time BTCC campaign? Personally I reckon not, i'd expect him to defend a possible WTCC title or fight for the title again in 2007, and as the dates will most likely clash, his focus won't be on the BTCC.
Considering Turner has the least amount of testing time, and the least amount of race time of the three drivers, I think so far he has done extremely well for SEAT.
My thoughts for 2007, would be for a return to 3 cars if this was logistically and financially possible for the team to do, i think they could benefit from the extra car, if anything its extra protection for their spearhead cars. If you get my drift.
However only if this didn't stretch the team's overall effort.