Unfortunately, not adjustable.
As Mahjik said, it might not be the best set-up and I should have gone for stiffer schocks like bilstein or tokico.

I can't believe Tein advertises that the S-tech were designed to fit OEM shocks...

i learned the shock/spring thing when i put stiffer springs in my Flex's, and the ride got better! Flex's are valved pretty stiff for the springs they come with.

Tein may have meant that the S-Tech's are designed to FIT OEM shocks, but are not necessarily suitable for the stuff that came with the car. There are a few OEM 'style' shocks that can be valved for any springs you want (Bilstein, Koni, etc)

You sure about this? I have had Teins for a few years now...did my research back in the day when I bought them, and from what I remember the Tein were linear.

thats just what the website says. i've never had a set. you can tell by the pic tho..

S.Tech Springs are of a progressive design. The straight springs which are provided with the coilovers are linear rate springs.

Josh 18_2k is right in saying the springs were designed to FIT your oem shocks. They were designed and tested to the best of abilities, however every driver has their own opinion and desire. If you desire a less sportier ride and want more comfort, but still slightly stiffer than stock, along with a drop in ride height you may want to look into H.Tech Springs. But that depends on whether you want to pay for another set.

That's just their marketing term as they are linear "rate" springs.