I have a 2007 G35S 6MT sedan. I have had Eibach Prokit springs on since 9k miles and have always felt the stock springs were a tad underdamped resulting in a ride with lots of float and bounce. Well several months ago, KONI tested the G37 coupe with their yellow adjustable sport shocks from the 2010-2011 Nissan 370Z and it fit perfectly--we know what that means...another option for our RWD sedans!!!
Bought a set from ebay vendor LTBAutosports since they had a very good price ($895 shipped) and are an authorized Koni dealer. I noticed though that their price went up after I bought my set. Today was install day. This is not a how2 but install was fairly straight forward if you've done springs before. And who doesn't love pics?
Here is the set:
The rears (bottom two) and not easily adjustable (rebound only) since you have to make turns using a something small (I used a small hex key) at the very top of the shock so it is best to set it to something that you'll be happy with before installing. I have had KONI adjustable sport shocks for 2 previous cars (and loved them paired with H&R on one, stock springs on the other) so from that experience set the rears to 3/4 turns (up to 1 turn is plenty for the rears). The fronts are adjustable (rebound only) from the engine bay so no worries (1/4 - 1/2 turn is plenty!).
Koni front strut next to OE strut:
I am comparing the lower spring perch in this picture because there have been at least one report that G37 coupe struts have the spring perch 1/2" higher than the sedan. However, side-by-side, the spring perches are roughly at the same height--this is good news! However I did notice that the front wheel gap has slightly more height after install--more on that later.
In a nutshell, jack front end, remove top 3 12mm bolts in engine bay holding strut from above, remove endlink from sway bar and lower bolt holding strut from below, remove bolt from arm attached to ball joint of upper control arm and remove brake/ABS sensor lines. Disassemble the OE spring/strut and put the mount/spring on the KONI struts with a spring compressor. Thankfully this is much much easier on a lowering spring! Then just put everythign back. Easy peasy.
Remove two 12mm nuts holding top of shock and the lower bolt holding bottom. You should use a jack under the lower spring perch to off-load the shock. Then save the top shock mount but remove the piston shield with bump stop integrated with it. Here is where I think Koni messed up on my set: The nuts included are a poor fit: I would make sure you have a metric M10 nut to secure the top of the KONI shock if the nut does not thread easily. The lower shock nut is permanently affixed to the OE shock so you will need an M12 nut--my KONI set did not come with this so make sure you have this or use the M12 nut that was used to secure the top of the OE front strut piston to the mount. Other than that, easy peasy! Also it is helpful to try and make sure the adjustment notch at the top of the shock is facing out.
The end results:
NOTE: measurement from the ground to the wheel arches shows that the fronts are about 1/4" higher than before. However, I am totally convinced things need time to settle. I am not talking about the springs since they are 3 years old now but the front springs have a new position in the upper mount upon reassembly which needs to settle. Most definitely, my eibachs settled quite a bit from the time of install to a year later. This difference is much smaller. I did not do anything with the rear springs to install the rear shocks, so unsurprisingly, there is no change in rear height.
I love it! The disconcerting float is gone. You immediately notice the ride is firm yet supple. You will feel road imperfections more like expansion joints and the like (not harsh at all) but the ride is definitely more composed and sportier. This is just initial impressions from a 40 minute ride. I will definitely get a better feel over the next week or two and after I get an alignment. BTW I had set the fronts to a 1/2 turn and the rears 3/4 turn. I will be trying 1/4 turn up front just to see the difference. In my experience 1/4 - 1/2 turn is all you need for the fronts. In a nutshell, major ride improvement over stock--and keep in mind, my stock struts/shocks only have 30k miles to them.