March 2022, ICYMI.
There are a few vehicles in World of Tanks where Additional Grousers will improve your top speed more than a Turbocharger would.
I explored the complete list of 1.15 vehicles to pick out these vehicles.
The SU-130PM, Object 274a and GSOR 1008 with the Polar Star 3D Style are available from October 18 at 05:00 through October 25 at 05:00 UTC for varying prices.
The Polar Star 3D Style for the GSOR 1008 is available separately for £8.55.