the 14.7 i think that is more a driver thing cause there have been some stock si’s running that also and then there have been some that only run in the 15’s
top speed i couldn’t tell you i had it to 110 once and that was fast enough for me
also were you sure it was an si cause ive seen a couple that are just ex’s with si wheels and spoiler’s on them im not saying i doubt you just be sure it was really an si