Although i only had a 156, i had a slight power loss, not much but after 3k it would go like nothing else but below 3k it was slow. i replaced the thermostat and now it fly's through all the gears.
I never suspected the thermostat would contribute to power loss( most people say bad mpg, temp gauge, heating not working properly) are symptoms of a failed thermostat, it was a friend who said he had a civic vtec. his thermostat was broken and it wouldnt vtec at all. when he got it sorted it was all fine again.
Just read end of post, least its fixed just ignore my comment lol