Mercedes have introduced a series of upgrades onto their car at the Belgian Grand Prix this weekend. The Silver Arrows are gunning for a third victory of the season at Spa. They’ve made improvements to the beam wing, floor edge and diffuser. George Russell was seen running a unique test with thread-like instruments on the halo, which has also been tweaked. Mercedes won back-to-back races in Austria and Great Britain but lacked pace relative to McLaren at the Hungaroring. Lewis Hamilton managed to extend their podium streak to five races as his former team took a one-two. Hamilton had to fend o…