I just installed some Tein S-tech on my buddy's S2000 yesterday and they were very nice. The ride quality was very nice and lowered his car a good 1". Because they're progressive springs, they feel really good around town driving, yet still stiff enough for some corner carving. I'm sure you can't go wrong with either one.
Hint: Check ebay. We bought my buddy's S-Techs on ebay for $100+ $24 to ship. Good deal!!
If you have any more questions, you know where to find me
i have the tien springs and i almost bought the eibachs. both are a good choice i went with the tiens for the ride hieght i was looking for for wheel fitment.i even have 28x11.50x16 in the rear with no issues.just my 2 cents