I'm a proud owner of a 2007 Hyundai Sonata GLS with the 3.3L V6 option. I done quite a bit of mods so far but the one I'm most proud to this point is the Eibach Pro Kit lowering springs I ordered through a vender on Amazon. It avertised that it was to lower the car one inch front and rear. The spring kit I received was concidered a "series one" which has been discontinued by Eibach a while back. It lowers the front 1.5 inches front and 1 inch rear which produce a slight rake which I really like. It had non-adustable ball joints so I had to order some from Eibach. That's when I found out they didn't fit even though the website said it should fit. After a weekend of research I found out that the '06 to early '07 uses different upper control arms than the mid '07-'10 model Sonatas. When I informed Eibach of the difference they took the ball joints back at no cost and changed the application info on their website. I ended up buying adjustable ball joints made by Duralast that was made to fit Honda Civics and they fit! That led to another problem. The Eibach ball joint slide back and foward at the bottom of the joint while the Duralast adjust by turning a big nut on top of the joint. I decided to take it on it's first road trip this past weekend. At trip from San Antonio, Tx to Fresno, Ca. On the way back it started having a loud bang on dips and waves on the highway like it was bottoming out. When I got home today I realize it was the top of the ball joint nut hitting the upper fender well after the springs "settled" a quarter of an inch on the trip. The fix was simple. I had the shock tower notched with a 2 inch square so the control are had clearance to move up and down and the problem didn't re-occur. The lesson here is to do your research before any project and even then every vehicle isn't the same and things might have to be made to fit. It was a learning experience for me that's for sure. I hope this can help others that want to jump into a project for the first time. It is hardly ever done right the first time and if you learn something from it spread the word and help out your fellow car nuts out there.