lurchi, Tanaka is slightly keen for me to apply this to the AI Improvement Mod, so I'm having a closer look!
I really like the changes to early game drives as the jump from speed 2,000 to 12,500 is far too extreme. Cool.
What I'd suggest reconsidering is the late game, where I consider default speeds to be far too slow. It's often a mop-up operation, faster speeds would help speed-up the late game. So I would prefer more than default speed, not less ... at least once you get to Tech Level 5 and above.
Also, once Gerax is available, I'm finding in the AI Improvement Mod that there is little incentive to focus early on Hyperdrive research, as other areas provide more significant benefits. This may change if there was more of a range in Hyperdrive speeds. It always struck me how limited the change was from Tier 1 to Tier 7 ...