worth it? i think so...
true, the ga16de motor powering the sentra isn't terribly fast, but it has potential.
just like the d-series (non-VTEC) motors in hondas, the ga16de responds well to tuning. and with the recent NPM articles about the 200SX project car build-up, turbo is fast-becoming a distinct and affordable possibility.
from what i've read -- in more than one publication -- the base 1.6 liter sentra responds much better to mods than its fellow honda equivalent. sure, this was a car meant to get groceries, not tickets, but there is quite a bit of power to be unleashed in that tiny engine.
i believe.
have a little faith and patience and you will be duly rewarded.