"There's lots of other stuff going on. All the stuff that bolts to the back of the car and all the cooling that requires will be completely different next year," Scarborough says.
To ignore all these changes would mean being uncompetitive in 2014, says Allison.
"So, (the E21) needed to be developed while being squeezed on both sides from 2012 and 2014 -- that's a significant logistical challenge," Allison said.
Will tire changes make for a gripping season?
Pirelli's new tires are the most significant change this season, says Red Bull's Newey.
According to the Italian-based company, the introduction of new softer compound tires will improve laps times and increase overtaking.
"After a spectacular start with seven winners from the first seven races, the result at the end of the year was races with less competition and sometimes only one pit stop. This phenomenon was also observed in 2011, disappointing many fans," Paul Hembery, Pirelli's motorsport director said when the tires were launched in January.
"Our 2013 range of tires mixes up the cards once more to help overtaking and ensure two to three pit stops per race," he added.
Pirelli say that this year's hard compound tire (with new orange coloring on the tire sidewall) is "roughly equivalent to last year's medium compound" with the "performance gap between the different compounds now in excess of 0.5 seconds per lap."
Softer compounds mean quicker tire wear, says Scarborough.
"There will be no one-stop races because the tires just won't last that long. Drivers will have to manage the tires. Strategy is going to be really critical this year in terms of teams thinking 'do we go for extra tire stops or eek out (the maximum from) a set of tires?" he said.
"As we saw last year, if you try and run too long on a set of tires they drop off a cliff and lose all performance. That could happen quite quickly with some of the tires this year, particularly if we get a hot season."
The teams and drivers have been getting to grips with the new tires at pre-season testing in Jerez, Spain.
"With these tires, you're always on your toes," said Mark Webber and Jenson Button -- who topped the timesheets on the first day of testing -- and they talked of a "different feeling" compared to last year.
"I think it is a better tire. It will be tricky again in terms of laps and degradation, but Pirelli has done a great job getting a wider range for the tires.
"One thing that I have noticed -- you are able to go fast immediately, even on lap one. That is something that we couldn't do last year," Button told Formula1.com.
Who will set the pace in 2013?
So who will reign in 2013? Will Red Bull lead the way again? Can Ferrari claim a first constuctors' title in five years? Or will McLaren end a 15-year drought in their 50th anniversary year?
"I think you will have Ferrari, Red Bull and McLaren setting the pace. I don't see that any of them are going to have any degree of dominance. I think it will be a lot tighter," says Scarborough.
"But like last year I think you're going to get spurious results in the first third/half of the year as teams get to grips with the tires. You're going to have a situation like last year where Maldanardo can win in a Williams because they got the tires working right."