Williams' technical chief admits the team has had to make substantial changes to the car for 2015 due to the new nose rules.
The Grove team managed a sensational leap last year from ninth in the championship in 2013 to third, behind only Mercedes and Red Bull.
Some of that leap was undoubtedly due to using the field-leading Mercedes engine, but Williams also comfortably beat the other two Mercedes customers, McLaren and Force India.
But for 2015, team technical boss Pat Symonds has admitted the 2014 concept had to be substantially changed in order to accommodate the new nose rules.
The FIA reacted to the unseemly anteater-style noses of last year by tidying up the regulations, and on the cover of the British magazine F1 Racing it is now clear the front of the 2015 Williams is substantially different.
"The change in regulations offered us a slight headache," Symonds admitted on Wednesday.
"The new front bulkhead and nose geometry had much more of an impact than we had initially anticipated and the effect on the aero was profound," he said.
The new FW37 has a smaller, flatter and lower nose than its predecessor, albeit still with a stubbly protrusion.
Symonds said: "The team have worked hard on pulling back the deficit these regulations have made for us."