i think by far thats the most popular complaint for a tsx. its underpowered but u get rewarded with other luxury features instead.
i traded in a 05 tC (5MT) for a 07 TSX (5AT).
so its not a true comparison but i think the TSX would pull away from the tC. i also had a 99 Si that would pull away from the tC. the tC had a horrible top end pull. the vvt-i doesnt kick as much as vtec or i-vtec on the top end.
it'll be faster thatn ur 91 ls for sure but probably even against a rsx.