Damaging an enemy champion begins a 1.5 second timer. Upon completion, you gain 40% - 110% (based on level) attack speed as well as removing the attack speed cap for 3 seconds. Attacking a champion while the effect is active will extend the duration to 6 seconds.
6 seconds cooldown.
Attack speed bonus increased.
Lethal Tempo still isn't doing well on most champions, so we're increasing the strength of the effect.
ATTACK SPEED : [30-80%] ⇒ 40-110%
This is our first wide balance pass on the Runes paths! We've got a few case-by-case contexts in the tabs below, but are otherwise focused on ensuring no one option in any given row is overpowering its neighbors.
COOLDOWN :  ⇒ 6
CRUISING SPEED 1.5 seconds after damaging a champion gain 30 - 80% Attack Speed (based on level) for 3 seconds. Attacking a champion extends the effect to 6 seconds.
COOLDOWN 10 seconds
OVER 9000!!! Lethal Tempo allows you to temporarily exceed the attack speed limit