be sure you buy IK22 or IK24 DENSO sparkplugs
if you want more performace go with TRD
sparkplugs...i think it's from denso and it is IK24
anything lower will ruin our GTS engine.
u need "cold" sparkplugs for high compression engine.
IK22 has a "cold" number of 7-8
IK24 has a "cold" number of 9
the bigger the number the "colder"
and the bosch you bought i think has 4-5