Question

Will Acrobat without an item be boosted by Technician?

Answer 1

Yes!

http://www.smogon.com/dp/abilities/technician

Technician will activate on Variably damaging moves under 60 Base Power. Moves like Payback, Pursuit, and Revenge, when the extra power is added on, will get a Technician boost. Look at Payback like this:

PAYBACK:
50 1.5 2 = 150 BP. (Minus STAB)

Or

REVENGE / AVALANCHE:
60 1.5 2 = 180 BP. (Minus STAB)

Remember: Technician boosts ALWAYS get added first.