The RP20 is sporting a brand new configuration at Mugello, with the side-pods seemingly much more fitted, along with a new engine cover and floor.
After some strong practice runs, Stroll looked destined for the top five in qualifying, only to have his final run curtailed by the same yellow flags that halted Valttri Bottas's charge for pole, meaning the true performance of the upgrades was masked.
Perez, who leaves the team at the end of the season, will have the updates fitted for the Russian Grand Prix in two weeks time and the Mexican is eager to close the gap to Red Bull.
"They look really good on the updated package," Perez told Sky Sports F1.
"We only have it for one car, for Lance and it is looking good. I am getting it for the next race so. They looked good today so we should be able to close the gap to the Red Bulls."
"I think there is plenty to play for tomorrow. A good start and good strategy, there are a lot of things to play for. I am happy to lose the position to my team-mate though. The penalty I thought was a bit harsh with how the pit-lane is but tomorrow there is a lot to play for."
Stroll, who was granted the single set of upgraded parts due to his higher position in the championship standings, believed he could have split the Red Bulls on the second row had it not been for Esteban Ocon's spin in Q3, with the Canadian eventually finishing behind Perez even with the upgraded car.
"With the yellow flags, I couldn't get a lap. I would have improved. Fifth was possible, maybe fourth. We will have to try and get a good start [tomorrow] and try to get a good run.
GPFans is a multi-platform, multi-language brand dedicated to Formula One coverage. We bring you all the ins and outs of the sport, 24/7, everything from up-to-the-minute news and features to the latest viral stories and clips.
We believe that a new generation of exciting, outspoken drivers will make F1 more popular than ever before, and we want to give our users access to as much of their heroes as possible, on and off the track. From Lewis Hamilton to Max Verstappen, Daniel Ricciardo to Sebastian Vettel, we provide in-depth analysis of every every Grand Prix in the season, from Australia to Abu Dhabi.
With Formula One under the new ownership of Liberty Media, how the sport is being covered is evolving, and GPFans will look to be at the heart of this progression into new media, as one of the fastest-growing sites covering the king of motorsports.