Fast starts, tricky overtaking, lifting off the gas on straights. Formula 1’s new era of regulations could change the series in unexpected ways when the season begins with the Australian Grand Prix this week.

Max Verstappen and Lewis Hamilton, the two most successful drivers on the grid were critical in testing cars whose electrical hybrid systems promote unusual driving styles and make racing more strategic.

Four-time champion Verstappen stated the cars “no fun” and suggested they might be a factor in considering retirement, while seven-time champ Hamilton suggested the rules are too complex for fans to grasp.It’s a crucial season for F1, which expanded rapidly over the last decade by putting drivers’ personalities center stage and not focusing on technological detail and style.

The “big four,” as McLaren boss Zak Brown calls them, seem broadly similar in pace, with Mercedes and Ferrari, and even Red Bull perhaps having a slight edge in race simulations in testing.

At the final test, Ferrari revealed a rear wing that turns upside down for straight-line speed and an innovative mini-wing behind the exhaust engine. It also stood out as the fastest testing cars  in practice starts after other teams, especially Mercedes, were sluggish off the line.