McLaren is confident that it will not suffer any dip in performance despite being forced to make modifications to its diffuser following a clarification of the regulations after the Bahrain Grand Prix.
AUTOSPORT understands that McLaren, Mercedes and at least two other teams - believed to be Renault and Force India - exploited a loophole in the rulebook by have excessively wide starter motor holes, which assists with both airflow and downforce.
Holes for the starter motor are allowed under the regulations, but the rules do not extend as far as setting out precise dimensions.
The FIA issued a clarification laying down a maximum diameter for the holes after inspecting the cars in Bahrain, but McLaren principal race engineer Phil Prew claims that the MP4/25's pace will not be adversely affected.
"The modifications to the diffuser, for us, were quite small, and we don't anticipate it to have any real effect on performance," Prew said on Thursday.
"It certainly won't be better, but we're not anticipating any real loss of performance with that.
"We're hoping in terms on one-lap performance in qualifying that we're able to find a slightly better balance than we had in Bahrain, and we're hopeful that we can have a better showing in qualifying which, as was clear to see, one of our weaknesses."