Welcome...
I have an extensive knowledge of VS Saxton Hale, Death Run, Prophunt and Randomizer. Ask me things.
I've found out that spectators move at about 300.8% normal speed, which is 902.4 units.
Sometimes spectators can glitch, causing more time to go to maximum speed, faster max speed, and poor turning.
The noclip command makes the player go at 1504 units, which is 501.33% normal speed.
Using comparisons from the notorious Super Scout's speed, the highest speeds achievable by normal means are as follows:
188 % - NOCLIP
112.8 % - SPECTATOR
93.75 % - Demoman (Charge)
65 % - MAX SPEED
64.6875 % - Scout (Baby Face's Blaster Max Boost)
63.125 % - Scout (Disciplinary Action Boost
53.125 % - Medic
50.625 % - Pyro, Engineer, Sniper, Spy (Discipliary Action Boost)
50 % - Scout
48 % - Soldier (Escape Plan Boost 4)
42 % - Soldier (Escape Plan Boost 3)
40 % - Medic
37.5 % - Pyro, Engineer, Sniper, Spy
36 % - Soldier (Escape Plan Boost 2)
35 % - Demoman
33 % - Soldier (Escape Plan Boost 1)
30 % - Soldier
28.75 % - Heavy
Random Coloured Boxes! (just learning, thanks Ashes for the helpful info on the userbox problem I had... might make it 4xwhatever later on)