i had this issue on my corvette before so i called the tire manufacturer and he informed me that the tires i purchased were for a much heavier car so he told me to run less tire pressure than i was and it remedied the problem
an 1/8th of an inch wont cause pull like that. most alignment shops... suck.. if they charged you anything less than 200$ they didnt do it right. supra 4 wheel alignment is a 2hr job in the book.