You got new-car-itis and are trying to justify it with the higher price
of gas.

I moved from a '96 I30t that I bought new, to an '04 Accord EX V6 not
long ago. You probably know that this I30t is similar to a '96 Maxima
SE with the 3.0 liter. In the I30t, I got 23 mpg on premium, 21 on
regular (after the knock sensor died premium gas was of no importance).
The 3.0 liter automatic Accord gets 24-25 on regular in the same
driving conditions. The 2.4 I-4 might get about 27 mpg with an
automatic. I understand you want a manual, so add a couple more mpg.

Your Maxima is about ready for noise from the starter (grease dries
up), and maybe a broken driver's door latch and dead knock sensor too
if you have over 80K miles. Chances of a major malfunction are remote,
however, assuming you've cared for it.

The Accord does not have anywhere near the handling prowess you're used
to. The ride is jiggly compared to a Maxima, and the trunk is somewhat
smaller. The Accord is faster, gets better mileage, is equally
reliable, has a fairly roomy cabin almost on a par with Maximas (which
themselves are quite large for a mid-sized car). The leather (gasp,
I'll be flamed for this) in the Accord is not as durable from what I've
seen of friends' and will maybe fall apart after 5 years if you don't
put treatment on it.

The Accord is significantly safer if you get into a major collision.
The Accord 60 to 0 stops are even longer than a Maxima, which is also
pretty poor. So it is a little more likely you'll need that extra
crash protection.

The paint is crappy on Maximas but looks great for a few years. In
most colors, the Accord doesn't have the Maxima's great wet-gloss look,
but Accord paint generally will age better than a Maxima's.

Financially there is no question that you'd be better served by saving
up some money for repairs instead of trading in. If you simpy keep
your payments equal, you are financially committing suicide like most
people do, paying excessive depreciation year after year. End of
lecture.