The top speed of the M18 Hellcat has been a point of conversation ever since it was implemented. WG has set the top speed of the M18 as 72 km/h as of today. This however is lower than historical top speed and since the introduction of the Panzer I ausf. C speeds higher than 72 km/h are possible. The Hellcat deserves some more speed IMO. Many people want the speed to be 97 km/h, this speed however is only attainable is short spurts in perfect circumstances and still causes damage to the engine and transmission, lets not have that. According to US Ordnance Corps the M18's official maximum speed is 80 km/h. This 80 km/h mark is much more comfortable and reasonable top speed than the 97 km/h that isn't sustainable and isn't backed by US Ordnance Corps records.
Also in WoT the M18 can mount the M36 turret and the M3 90 mm gun, in this configuration the M18 goes from having ~23.6 hp/t to ~21 hp/t. I would expect that the top speed to decrease along with the hp/t ratio, so the speed in WoT of 72 km/h should be fairly accurate in describing the M18 with the M36 turret/90 mm.
I didn't want this post to be pic-less, so look at the 90 mm Hellcat.
In WoT it would be accurate and not game-breaking IMO to increase the top speed for the M18 Hellcat to ~80 km/h for the configuration with the stock turret and top engine. The top speed for the elite M18 is fine IMO. Just my 2 cents.
M18 Hellcat Tank Destroyer 1943-97 by Steven J. Zaloga
Stuart: History of the American Light Tank Vol 1 by R. P. Hunnicutt
British and American Tanks of World War Two, The Complete Illustrated History of British, American, and Commonwealth Tanks 1933-1945 by Peter Chamberlain and Chris Ellis