Here is the list of the speed upgrades I could think of, tell me if you agree or disagree:
Draken: Supersonic+
Mikey: At least Supersonic+ (Should be a lot faster than Draken)
Izana: At least Supersonic+ (Was able to easily land attacks on Mikey and block his attacks, should be faster than the damaged himself who saved Kakucho)
South: Supersonic+ (Could land punches on Draken multiple times and block a punch from him, though just barely), higher with dark impulses
Wakasa: At least Supersonic+ (Easily landed multiple kicks on base South)
Benkei: At least Supersonic+ (Easily blocked a punch from base South)
Taiju: At least Supersonic+ (Countered the legendary duo's attack and defeated them)
Senju: At least Supersonic+ (Dodged multiple punches from Dark Urges South and surprised him with her attacks)
Inui: Supersonic (Surprised the legendary duo with his attacks but got defeated shortly after)
Kokonoi: Supersonic (Surprised Benkei with his punch but got defeated shortly after, should be comparable to Inui)
Mitsuya: Supersonic (Was able to land a few punches on Taiju, who was using 70% of his power)
Mocchi: Supersonic (Fought on par with Mitsuya)
Chifuyu: Supersonic (Was able to defeat Mocchi)
Mucho: Supersonic (Countered Inui's punch)
Baji: Supersonic (Is one of the strongest captains in Toman, should be faster than Mitsuya or Chifuyu)
Peh: Supersonic (Stated to be stronger than Mitsuya by Mitsuya himself)
Kakucho: At least Supersonic, possibly Supersonic+ (Easily speed blitzed every Toman vice-captain, was able to land a punch on Benkei although he was off guard)
Takemichi: At least Supersonic, possibly Supersonic+ (Fought on par with Kakucho)
Sanzu: At least Supersonic, possibly Supersonic+ (Was able to cut Kakucho and counter Takemichi's attack)
Hanma: Supersonic+ (Was able to fight on par with Draken for a while)
Angry: At least Supersonic in Crying Blue Ogre mode (Easily defeated every Tenjiku Heavenly King other than Kakucho)