It is WAY easier to make awesome power gains on a factory turbo car, versus a factory NA car. For instance, on pretty much ANY turbo car, all you need is:

manaul boost controller (anywhere from $25-100)
downpipe/exhaust ($350-800)
piggyback fuel computer ($150-300)

Those three things on a turbo car can easily net 30-100hp, depending on the appilcation. Good luck squeezing anywhere near that much power out of an NA car for that cheap, without using nitrous.

For a 2nd Gen Eclipse/Talon turbo (95-99), you can probably score all of that stuff for like $500-700. It's all easy to install, and if you get the car professionally dyno-tuned (usually around $150), you can easily have all the extra power while maintaining fuel economy and reliabilty.

Plus, a 95-99 Eclipse will be a cheaper car to begin with (than a 00+ Eclipse).