Grosjean feels everyone is "going to have a B-car" in Spain

The first non-flyaway race of the season is traditionally when teams bring significant updates, although it has become more common for teams with greater resources to roll out new parts across the opening races.

Haas is usually strong at Barcelona and hopes that this form – combined with a new front wing, floor and other bodywork changes – helps it recover from a difficult start to the season in which its performance has been hampered by tyre problems.

Grosjean believes comparisons to how Haas's 2019 car performance in pre-season testing at the Spanish track will also help address those weaknesses, but said the early-season pecking order may shift anyway.

"You also know everyone's going to bring big updates," Grosjean said. "So it's almost like everyone's going to have a B-car, therefore the standings could be a bit different.

"I think it's important that our updates go in the right direction. It's important, as we know what we can do there. We'll see if we can repeat that and understand where our race pace has gone."

Several teams have struggled to get Pirelli's thinner-gauge 2019 tyres into an optimal working window this season.

Haas seems to struggle with tyre graining more than others, but independently of its "big" upgrade Grosjean does not think tyre performance will be an issue in Spain.

"It's a track with high energy, so I'm not too worried about getting the tyres to work, in theory," he said. "It's interesting, as we definitely got them to work in winter testing. Going back there and seeing if we can still get them to work will be a good test, because we know the car should be fast there."

Haas team principal Gunther Steiner said the "significant" updates, his team's first of the year, will provide a litmus test.

"A lot of parts on the car will change – the front wing, the floor and a lot of the smaller parts, like mirrors," he said.

"We have a lot of data. We need to make sure that everything still correlates after four races and that our upgrade works, as well. We're looking forward to it, to see where we compare from our time there in pre-season testing.

"It isn't really that you can go back and compare the first four races, but Barcelona always affords a good point to regroup after the early long-haul races. We're back in Europe, we've got upgrades coming, but you've got more to look at with Barcelona because we ran our pre-season testing there."