Just got new Teins flex have some questions about seting ride height and spring pre-load. I would like to lower about 1". I don't know if this will mess up front allignment? caster? Can some one who has set these up please give me some help?

 

Lowered mine one inch. You will be slightly out of spec., but will only affect treadwear 10% or so. Steering, handling will be fine.
Just do a four wheel alignment and four wheel corner-weighting.
Adjusting the ride height is no fun...the guys at my shop did not enjoy it at all. Good luck.

 

Well any time you lower a car it will affect the alignment of the car. I have the same set up and on speed bumps and steep drive ways you'll scrape and damage the flex pipe of your exaust. The flex pipe of the exhaust is located on the y pipe. Mine is shredded right know but the car looks great slammed. Here's a pic