Easy/cheap ways to improve low end torque?
 

I read about advancing (or is it retarding?) the timing 1-2° but does that really help? I have a friend that would be willing to do it for free and then change it back for smog. Also, would tuning the ECU help? With that being said, would advancing/retarding timing effect mpg at 65mph?

I advanced my ignition and cam timing. And also increased valve lash. I guess there could be more cam wear, but I have plenty of extra camshafts. The big difference, while not as easy, was the 8-valve conversion.

Advancing can increase nox due to slightly increased cylinder pressures. This increase is also why most 80-90's car can benefit from some advancing (were retarded relative to ideal from the factory).
Can it improve your car? Depends. A D15z1 is advanced about 4 deg from the factory relative to all the others, and is why it has different timing marks. I have tried advancing and retarding it in 1 degree increments (-4/+4), nothing was better than factory. You would have to look at your car to tell.

If you're looking for low end, cut weight. Either from the engine, or chassis. Gearing will help too, but is just done off of the final drive will hurt highway mpg. There are other ways, but they can be hit/miss and not easy or cheap.

Well I have a VX tranny in my HX so I like the tall gearing, I just wanted a little more torque so when I take off I don't take off like a snail.

I'd just rev it up a bit more. If you look at the BSFC maps, there isn't a huge penalty for going to higher rpms (vs lower load).

I'm with Daox, don't try to increase the torque. If you advance your camshaft, you gain low end torque but you also lose part throttle efficiency.

This is the cheapest and easiest way to increase torque...

No wonder 8-valve engines are still popular back here :D

I've read somewhere that longer intake mainfold will increase low end torque but you'll suffer in terms of high end power. But to build a mainfold is not cheap or easy anyway :)

I did A-B-A testing and I actually gained 1-2 mpg going up to 3k RPM then shifting vs 2,250. Idk. It's the same street and I have repeated the test about 10-15 times within 1mpg difference so yea. I have been shifting at 2750-3k recently.