Can this be done or not and will it negatively change the handling. If so, what the easiest and cheapest way? I'm not sure I want to lower the front end but I would like the rear to match the front. Thanks.
I did my rears first and drove around for a week, until I could do my fronts. Although I used Eibachs (rather than the full WW method) on my regular CTS, the rear dropped one inch. You'll definitely notice the difference in feel of the car and the headlights will blind everyone with only the rear lowered, but cutting half a coil and installing the WW spacers is a very easy way to get th rear down a little.
By the time it was all done, I lowered the front about 0.8" (Eibachs with WW shims) and the rear around 0.9" to 1". It sits slightly more level and the wheel gaps are now where they should be (around 1"F/1.5"R).
Adjusting your car to even wheel-gap will trade handling for looks. If you bought the car for looks then do it and take the Vbadges off your car. If you bought the car for performance shake the idea out of your head. I don't mean to sound like a d1ck, but wheel-gap parity wasn't on the suspension-engineer's mind when they ran the Nurburgring trying to engineer a top-handling muscle sedan.
I just re-read my post and realized I left out a minor clarification (and you're completely right, ace). When I lowered the rear only (only had a few hours each weekend to do each of the front and back), the handling that I 'noticed' was 'uncomfortably odd'. I also didn't add the obvious : 'not recommended'.
During that week, I knew better than to push the car in corners (on-ramp of a highway cloverleaf). It's much more neutral after finishing the front, but then I realized I need to upgrade the sway bars to match the performance of the Eibachs and V shocks. WW is coming to the rescue again for me here. I'll have them on before the new year.
The Eibachs on the regular CTS are very close to stock FE4 spring rates. The fronts are linear (68N/mm) with the rears being progressive (43N/mm to 69N/mm - softer when extended above the static ride height, like when cresting a hill, and the stiffer at static ride height and compressed). Incidentally, Eibach confirmed that the rear springs are the SAME part for the V and the CTS kits. Since my car is about 350lbs lighter than a V, the result is a very firm ride, likely in the ballpark of a V with FG2's (I have FE4 shocks on it now).
I really like the handling of my V but wanted to improve the looks a little. I'm not sure I want to lower the front because of potential car wash problems and parking lot bump stop problems as other members have mentioned. Ace, I appreciate your passion about the V's handling but don't make a guy feel stupid about asking a question. I wasn't sure, that's why I asked.
I didn't mean to come accross that way, it was not my intent...my appologies. I am quite passionate about keeping ANY vehicle's handling balance in the "safe" zone, and sometimes that shines through a little too much. With the V having the power it does, and power-on oversteer not being difficult with a stock set-up, going lower in the rear will cause the car to act like a "drifting" car...and I'd rather not share my emotions on that subject at this moment.
If you'd like to change the gaps, it will need to be done to both ends. There are several ways to accomplish this but for your application I'd lean toward the Wildwhl mod. If you do a search on Wildwhl mod, you'll find quite a bunch of info/testing/data that should work for you. Off hand, I'd go with no more than 1/2 inch drop if you're hesitant about carwashes/speedbumps. Either that or switch to a 255/45/18 tire on the stock rims, they'll fill in the gaps a little...*you "may" have slight rubbing on the inner fenderwells, nothing drastic but noticeable by the brake ducting.
I just got off the phone with Eibach. When you lower the rear of the CTS make sure you preload the suspension BEFORE retightening all bushings, and make sure to torque to factory settings. If you don't do this it will affect the ride height.