strange, my ride with teins is pretty much near stock.
also beware that there are a lot of fake teins floating about.
I got mine from Demon Tweeks years ago, as I say they may have changed them but mine were awful. The Eibachs are so much better in terms of ride quality even they are a fair bit lower.
The Teins do have a harder spring rate but on paper they aren't too different.
My Z came with the Teins on already so can't comment properly unfortunately