Not necessarily, there were Sparrows with different speeds in D1 as well. Like the overdrive Sparrow, had lowest speed however had the highest speed when using overdrive and using boosts to your advantage to get insane speeds. Trick Sparrow were high speed overall but can be beaten by good overdrive users. Except in D2 we don't have the trio of Sparrows like D1, so all they have to do is make them all one set speed in SRL. Easier honestly.