I mean akuma, that I've spent 5K+ on engine mods alone, mugen 4-1 extractor, 5 zigen muffler and downpipe, catback system, HKS air suction kit (becoz I cannot find mugen one for eg) and I've yet to get signifigant gains like you say across the RPM there's always power lost/no change somewhere, and made up (of course, more than the one lost lah!) somewhere else. I know I can get it once I go for tuning (still undecided what piggyback/stanalone to use), but overall in the end, the only mod you can get to increase your power through the entire rpm band above is through tuning, but NOT through bolt-ons alone, which was what I was saying all along. That's why I think you're expecting too much out of bolt-ons.
But piggyback/stanalones are not 1K++... more like 2-6K. Unless you're talking second-hand, which depends on your luck entirely.