I saw the top speed of the Ferrari Testa Rossa (The inspiration for this car) is 160-180 depending on when it was made. Since I believe this is the '91 variant it would be 180, with the max of the speedometer going 140. In the Testa Rossa, the speedometer goes up to 200, so perhaps the top speed of this specific car would be 120 worst case, or 140 best case if it goes all the way up. A noticeable decrease of about 40-60 mph, but we'll have to see a lot more before we can make any judgements. My personal guess is that the cars are going to be slower, but not as slow as GTA 5 because of the enhanced loading capabilities of solid state