I don't really want customer cars. In their day they were useful, because budgets were small, and customer teams were tiny. It was rare for customer teams to do particularly well (but not unknown).
But these days, will mega-budgets, huge exposure, and vastly more complex cars, I think that it should be a constructors only sport. STR and SA are breaking the rules in my book, and I think Williams has a good point.
If customer cars were only allowed to be used if they were last years cars or earlier (in the case of rule changes then customer teams will be required to modify last years car, not default to the current car), then I might agree. But I don't want McLaren to have a 4 car entry, which is what the current Prodrive deals seems to amount to.