Mar.2 (GMM) Lotus has overcome a serious chassis flaw to lead the field as the final pre-season test began at Barcelona.
The former Renault team had to sit out last week's running at the Circuit de Catalunya as designers grappled to fix a problem with the front suspension mounting.
"The mounting of the suspension is now the strongest part of the car," an unnamed team member is quoted by SID news agency.
At the end of his return to action on Thursday, Romain Grosjean was quoted by France's Auto Plus: "It (the E20) feels the same, there's not much difference really."
Indeed, the revised car is 1 kilogram heavier, but the biggest issue is the four lost days of testing, which after an FIA clarification cannot now be made up.
"To miss four days is not ideal as suddenly we have to try to work twice as hard to catch up," continued Grosjean.
"It's true that it's not great, but it's not as problematic as it might have been."
He is referring to the fact that, so far, the Lotus appears intrinsically fast.
Asked if the E20 felt as good around Barcelona's demanding layout as it had at Jerez last month, the reigning GP champion enthused: "Yes, exactly the same.
"You can trust the car, push it, play with it.
"You can attack, and if you attack too much, you know what will happen -- if you have understeer, you know that by attacking less, you'll have less understeer.
"On this aspect, the car is very good."
1982 world champion Keke Rosberg told the Finnish broadcaster MTV3 that while the Lotus looks as good in Barcelona as it had at Jerez, it is still not clear if it will be able to compete against F1's regular top teams.
"Behind them, it's a lot closer than it was before."
However, amid F1's now extremely limited track testing regime, there is no ignoring the four lost days of running.
Asked if he is ready for 2012, Grosjean said according to Finland's Turun Sanomat: "I have to be.
"Of course, the more time you have with your car, the better you feel. However, it is what it is.
"We have this four days prior to Melbourne and that's better than nothing," he added.
- Caterham had to replace Heikki Kovalainen with his teammate Vitaly Petrov on Thursday, as the Finn recovered at his nearby hotel with food poisoning.