Improving the bends is probably the most beneficial, just try to avoid any 90 degree angles or sharp bends. Also, upgrade the intercooler with the pipes as someone has already suggested. Smaller and larger pipes have their benefits. I personally use 2.5 pipes on most of my setups. Unless I am boosting 20+ psi and/or using an extremely large turbo, then I use 3" and a larger intercooler. The majority of the air will travel against the walls of the tubes, so think about how to keep the air flowing smoothly. Spaces between pipes, sharp bends, and differences in pipe sizes all cause turbulence in the air flow.