I was wondering is this car any good to mod, or if it's worth it, im stuck with it for atleast 6 years. Thanks in advance.

No.

Well, you could always try to get a different engine for it. There is the Sentra SE-R Vspec, which is a decent car (not necessarily a pavement crusher, but not bad for the price), you could look into swapping parts and what not to get to that level at least. I don't really know Nissans well though, so I'd suggest searching google to see what you can find.