Paul di Resta is hopeful the upgrades package to be introduced by his Force India team in Spain will mean a "fairly big" boost for the squad.
"I wouldn't put any numbers on it, but we are hoping it's going to be a fairly big margin here," di Resta said on Thursday. "I suppose that depends on the rest of the grid. We've not been too far away from making it to Q3 in the last race. We were only three and a half to four tenths away. In China we were pretty strong too. We are hopeful our upgrade is bigger than what they have."
The Silverstone-based squad is introducing a new aero package which includes new wings as well as a blown floor. Di Resta admitted it is yet unclear if the team will decide to keep all the updates in the car all weekend until they see how they work.
"I'm fairly reserved in that matter because at the end of the day we won't know until we get on track," he said. "We are going into it with an open mind. Obviously the team has done the best job possible, but until you get it in the car...
"We've seen many teams trying many different things and not racing them. We are fairly reserved but I'm sure the team will do a professional job and make sure that the right approach is needed and be sure that we put what we think is the best racecar on track on Saturday morning."
He added: "It's been very difficult to simulate them and I wouldn't say we've got a full direction of which way going to go."