I've just calculated the stats using the stat formula (I'm assuming a +Atk nature, fractions rounded down)
(((25[IV]+(2*134[Base Attack])+0[EV's])*99[Level])/100)+5)*1.1[Nature]=324 Attack
(((25[IV]+(2*134[Base Attack])+252[EV's])*100[Level])/100)+5)*1.1[Nature]=397 Attack
That's a difference of 73. Hope that answers your question.
(((25[IV]+(2*134[Base Attack])+0[EV's])*99[Level])/100)+5)*1.1[Nature]=324 Attack
(((25[IV]+(2*134[Base Attack])+252[EV's])*100[Level])/100)+5)*1.1[Nature]=397 Attack
That's a difference of 73. Hope that answers your question.







