Ducati Marlboro's Casey Stoner is in the best shape of his life as he goes for his fourth win in a row in the season-opening Qatar Grand Prix.The 2007 World Champion has enjoyed an incident-free off-season following the diagnosis of his lactose intolerance late last year. With a change in diet, Stoner was able to concentrate on training, which has raised his level of fitness to a new level.That, and a revised firing order in the Desmosedici GP10, have been encouraging signs as the Australian begins a campaign that should be his most successful in years.Stoner said that having only three two-day tests had made it a long winter, but that he'd "sorted our issues from last year and I hope that we can have a longer, more successful year than what we've had in the past. So we're definitely going to give 100 percent and see how it goes. And on Sunday night is where it all starts."Halfway through last season Stoner suggested to Ducati's technical wizard Filippo Preziosi that they consider changing the Ducati to a big bang firing order. When it was delivered, in a test the day after the season finale in Valencia, both Stoner and teammate Nicky Hayden were immediately impressed."I mean, the chassis we had at a very good point, but we just couldn't still get the bike hooked up out of the corners," he said. "So we needed that extra torque, the smoother engine delivery and we've definitely got that with the engine. Of course, there's a few small setbacks with the new engine. We've lost a slight bit of top speed, but I believe with the extra acceleration we're getting out of the corners we're not losing anything in the end anyway. So we're very happy with the way the bike's going."The biggest difference is definitely at the end of our tire life. Where in the past we wouldn't drop down just a little bit in tire performance, we'd drop down a lot. With this we actually don't find almost any dropdown whatsoever. It's a lot easier to ride at the end of a race, I think. And we're yet to see. I suppose I want to get the first five or six races underway in a lot different conditions, a lot different circuits and then we can really know whether we're going in the right direction."Stoner said not to expect big changes throughout the year."What we start the season with we basically finish the season. We have maybe one or two things that we can add to it throughout the season, but they're a very small part. Normally we just work more with the bikes and eventually we find something inside the bike that we didn't find in the beginning of the season. So I think the best thing to do is just slowly work along with it. We had a definite competitive enough bike last year to challenge for a championship, but unfortunately I didn't do the job. So I think this year, as long as I do everything I can I believe we've got a good chance."