So I called up THMotorsports.com and spoke to Eddie, who is a super helpful and nice guy, and ended up purchasing the KW v3. After anxiously waiting the for the coil overs to make the 7 day journey from Germany to my car, I finally got a box!!!
The installation was very easy, except the front bolts were very tough to tighten down to the specified 80 lbs of torque. This is because the stock front top hats are recessed and required the use of a midget wrench and a regular wrench and a lot of elbow grease.
After first installing the coil overs my car was very low, less than a finger gap in the front and rear. The car handled well but seemed to bounce quiet a bit. I decided to raise the car for more suspension travel and at the same time adjusted the bump/compression setting under the shocks. Stock, from the factory, the setting was all the way soft and thats why I experienced the bouncing, after setting the bump/compression and rebound to about the specified settings the car felt completely different and super solid. Now my settings are 2 turns from full hard on the front and 1 turn from full hard on the rear. Rebound is set to 8 clicks front and 10 clicks rear from full hard.
Before the new settings my rear would break out in first gear at the slightest turn, now my car sticks to the ground at hard throttle around turns in 1st gear. The car feels completely different, the compression adjustments can be felt, unlike adjustments on some lower grade coil overs. The v3's are great coil overs because you can set the ride to be comfortable or super sporty, the spring rates are not very aggressive and help the car grip the road and allow the exquisite dampening to replace the super stiff spring rates.
December 13th I will be running my first autocross with the new coil overs and I will update this post.
So far I have to admit that Eddie was right, these are the best coil overs for the price, and are the best suspension I have ever owned on the IS300 (and I owned quiet a few suspension set ups over the years). Right now I also have the L-Tuned red sway bars with the rear set to the stiffest setting.
Thumbs up to KW and THMotorsports!