Plato made the best of tricky, changing conditions to win the feature race, while Aiello proved that the Nissan is currently the quickest car in the series with a dominant performance in the dry sprint race.
Plato made a great start to the feature as rain started to fall, weaving through from fourth on the grid to take the lead on the exit of the first corner. Thereafter his win only looked in doubt shortly after he had made his compulsory pit stop.
Then the champion, Rickard Rydell, challenged him hard. Too hard as it turned out, when a steering arm on the Swede's Volvo broke after the two cars touched briefly. That put Rydell out of the race, but his speed then and in the earlier sprint race showed he will be a title contender again.
Plato duly took the win ahead of Yvan Muller's Vauxhall and to complete a great day for Renault his new French team mate, Jean-Christophe Boullion, was in third. Muller's car failed a post-race ride-height check but he retained his second place.
Aiello had earlier opened his BTCC account with a win in the sprint race. The highly-rated French driver took advantage of a slip by his team mate David Leslie to take the lead half way round the first lap, and never looked back. Leslie made it a Nissan one-two.