Lets say a Swoobat is up against a Yanmega which it outspeeds without the Yanmega having a Speed Boost. If the Yanmega had a few Speed Boost up would the Swoobat outspeed or will it be outsped because of the Speed Boost.
If the wielder is the target of an attack, all of the attacker's Attack, Special Attack, and accuracy stat stages are ignored during damage calculation and accuracy checks. If the wielder is attacking, all of the defender's Defense, Special Defense, and evasion stat stages are ignored during damage calculation and accuracy checks. If the wielder uses Punishment or the opposing Pokemon uses Stored Power, stat boosts still factor into its power. If the wielder hits itself in its confusion, its altered Attack and Defense stats are kept during damage calculation.
It doesn't mention speed so my answer is that yanmega will outspeed through the speed boost
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