Vimd is approximately the best range cruise speed for a piston engine aircraft, and approximately the best endurance speed for a turbo jet aircraft. Any beginner's principles of flight text will give you more information.
If you rotate quite early, you may "unstick" earlier, so use less runway to get airborne (reduced TORR). However, you will be airborne at a low speed and high AoA, therefore have high induced drag and be less likely to maintain a normal climb gradient. TODR may be increased.
Just bear in mind that I've given answers based on some wild assumptions on my part, and on some experience of questions examiners like to ask. Mustafagander is correct - don't try this yourself in the real world, where assumptions may kill.
Cheers,
O8