Last year proved to be a nerve-wracking winter period where many thought that the new DW12 chassis from Dallara and new-specification engines from Chevrolet, Honda and Lotus would never materialise in time for the start of the 2012 IZOD IndyCar Series season.

Even if it did, many drivers and teams wondered whether the car would ever prove drivable in race conditions. But now, as the DW12's maiden season draws to a close, the drivers have given the thumbs-up to the new hardware at the end of the 15-race calendar.

"I definitely give it thumbs up," said championship leader Will Power speaking at Auto Club Speedway in Fontana, California, ahead of this year's final race. "B plus. It's been good. It's been good racing."

Not that the car is perfect of course, with Power pointing out that the car was definitely somewhat rear-heavy at the start and adding: "Still is."

"From where we came from the beginning of the season, from pre-season testing until now, definitely a big improvement," agreed Ryan Hunter-Reay, Power's sole remaining challenger for this year's title.

"At first it didn't seem like it had a shot at being a very nice car," admitted Hunter-Reay. "Now, yeah, I'm enjoying it, especially on the road and street circuits. It was fun on the short ovals. You know, on the big tracks, we've had some of the best races we've ever had."

As for his own grading of the DW12, Hunter-Reay proved to be a slightly more lenient supply teacher than Power: "I think it's maybe an A minus, right in there."

But favourable grades aside, there's still plenty of things that the drivers would like to see improved over the long off-season from now until the start of 2013 season next March.

"I need a little less understeer right now and then I'll give it some more," said Hunter-Reay. "The drivers would like more horsepower. We've always wanted that. That's kind of nothing different. Another 100 would be nice."

"Carbon gearbox!" was Power's request.

One of the most controversial aspects of the new design had been the semi-covered wheels. Some thought that this undermined the fundamental spirit of open wheel racing, while others felt that the safeguards simply wouldn't work in race conditions.

But while there have still been some incidents of wheel-to-wheel contact during the year, there have also been plenty of examples where cars have been able to race hard, make contact, and not have a serious wreck as a result.

"I think it's been successful safety-wise, too, with the wheels closed in," agreed Power.