contrails and high g trails - both would be really great and add a lot of eye candy to furballs.
to be honest, cheap computers (like 400 dollar desktops) are good enough to handle anything that Ah2 has to offer and can do more - and honestly - if you are using a computer that is worth less then 400 dollars, then you should not be playing fps style dogfighting sims. I know there is an argument against setting the standards too high, but setting the standards to th lowest of the lowest computers is also equally idiotic.