Sylas builds
So he is an AP champ correct? But he also wants to Auto attack to utilize his passive.
This makes me feel
will be core.
AP and AD Activate slow to get in range for his E Sustain on all his damage.
So I would think depending on his CD AS and Mana costs.
or
+ 
EDIT:
This is more of what I run after playing him
or DEF item if needed. Boots are only if you need to run away. If you can fight then no boots is fine because no one gets away.
Ult that adds 249 damage foe his Ult 1098 max damage
I get +1250 damage on his Ult.