The Haas F1 Team has confirmed that it's bringing a major set of upgrades to the VF-19 for this weekend's Spanish Grand Prix.
It's the squad's latest attempt to get on top of the tyre heating issues that have impaired their race performances over the first four races of 2019.
However only Romain Grosjean will get the opportunity to try out the new parts in Friday's free practice sessions at the Circuit de Barcelona-Catalunya.
It's been decided that his team mate Kevin Magnussen will initially stick to the existing configuration to enable the engineers to do a proper 'compare and contrast' benchmark study.
"What we are doing tomorrow, we will run one car on the old spec and one on the new spec, so we have something to compare," said team boss Guenther Steiner.
"If with the new spec we've got issues at least we can compare it," he explained. "If you put two cars on the new spec and you've got an issue, [the question becomes] is it the tyres or the new spec?
"So we've got one [old] and one [new], and then we can convert the second car on Friday night if everything goes to plan."
Steiner added that holding back on upgrading Magnussen's car on Friday wasn't down to a shortage of new parts available on site.
"We've got all the parts. We consciously wanted to have a back-to-back, and not to confuse us more with the tyre issue.
"I think we know what we need, but we don't know how to get it," he admitted. "It is as simple as that."
Haas started the season well Magnussen netting sixth place in Melbourne, and has also rated highly in many of the qualifying sessions.
But since then, problems with getting the tyres into the right operating temperature window for the race has meant that neither driver has managed to finish in the top ten in Bahrain, Shanghai or Baku.
"We just need to get in the window by running the tyres warmer. It sounds almost too simplistic - you could be asking, 'Why are you not doing that?'
"[It's] because we don't know how to get the temperature in the tyre. We are not the only ones. But maybe we are affected more than other people, I fully admit that.
“The brake gives you a certain amount of energy you can put in, there is not more,” he added. “The brake cannot create endless energy to heat the tyre up.
"The brake is not made to heat the tyre, because then you overheat the brake. As with Romain in Baku, at some stage we overheated the brakes because we tried to push too hard on it."
Steiner is hoping that warmer weather conditions and higher-speed corners in Spain will be better suited to their car.
"It cannot be worse [than Baku]," he acknowledged. "Here we should be okay. We were okay in testing, we were okay in Australia.
"If we are going backwards, it will be like: 'What happened?!'"