James Allison says Lotus will only add a modesty panel to their E21 if they "find one that develops downforce".
Lotus took the covers off their 2013 challenger in a launch that was broadcast online via the team's official YouTube channel.
The most notable feature at first glance is the stepped-nose which Lotus have retained and without the cover of a modesty panel.
Explaining the team's reason, technical director James Allison said a "cosmetic panel would weigh a few grams".
He added that the team would only include it if they "find one that develops downforce we will add later".
As for the car, the stepped-nose is not the only featured carried over from last season although there are also some changes.
The rear of the E21 is packaged more efficiently than last year's model while the new car also features sidepods similar to last year's Red Bull racer.
"I can assure you that we've done a lot, the whole team has been putting their heart and soul into this thing for quite some time," said Allison. "There is a lot gone into it and it is going to be an exciting car.
"The rules for 2013 are very, very similar to 2012 so you can expect a lot of family resemblance from the 2012 car, but the devil is in the detail and it adds up to a significant amount of performance.
"There are lots of new ideas and same concepts we have been pushing on with for a few years."
Allison confirmed that Lotus will continue with the passive DRS system they trialed last season.
"This is an area we continue to work on and the passive nature of the switching of our device means it is not outlawed by the latest regulations.
"It is not something which will be a silver bullet to transform our car, but it is something which could add performance as part of the overall design."
Lotus Unveil A 'Nice' Stepped-Nose E21