That's a pretty broad range. Usally desert riders crave top speed running (Top-end) and trail riders want low-end grunt. Either way, for trail riding or low-mid range power, it seems like a good reed spacer and flywheel weight seems to do the trick. Also, sending off the cylinder to be ported to your desired powerband. That is the best mod. Pipes have a small effect on power, but FMF makes a few pipes to the desired powerband. PC also makes good pipes, but have little experience with them.
Let us know what type of power you desire (e.g. smoother power, more torque, more HP, overall HP, topfuel, ect.)