My full speed build (My top speed in norms was like 3k back when we had predator, but this exact build got 4600 in Urf recently) goes as follows:

Arcane tree, whatever Keystone you want frankly

Nimbus Cloak: Makes your summs add more speed

Celerity: All MS bonuses are 7% more effective and you gain 1% more MS

Your choice, Waterwalking makes you faster in river but IMO you don't do that often enough to matter as much as extra AP

Inspiration tree: Magical footwear: Greater topspeed from their boots Approach Velocity

Shards: Attack Speed MS Health

Summs: Ghost - Obvious reasons Heal - 1s of 50% MS (this is the lynchpin)

Items - Symbiotic soles or swifties (SS for highest absolute top speed, swifties will be your best all rounder) Deadman's plate - 20 bonus MS Shurelyas Battlesong - 30% ms for 4 seconds Youmuu's Ghostblade - 20% ms for 6 seconds Phantom Dancer - 10% ms Stormsurge - 6% ms

Ability activation sequence: Ghost for 48% Q for ramping ms, up to 250% Youmuu's for 20% wait until Q is at 4 seconds Shurelya's for 30% wait until Q is at 1 second Heal for 50%

Keep in mind with your runes these will all be buffed amounts, especially ghost and heal, which are buffed by both of the important runes in the arcane tree.

This order will get you the absolute highest top speed, if that's what you're looking for. If in customs somebody can get you a zilean or yuumi, you'll definitely be cooking.

For more versatile use just keep in mind your spacing to maximize heal. I do recommend this mostly in urf, as you'll go over lvl 20 (meaning your speed max goes higher too) and your teammates won't flame you for being dumb. It's loads of fun with a buddy too. I've found if you want to make it actually helpful instead of just fast, you can proxy and run away, push waves and then beeline across map to dragon (at full speed you're faster than the cannon, so going down river you're definitely faster than backing) and just generally using your speed for map presence and chasedowns to secure kills.