[Bamarider]

So I have an 07 gt convertible that I just ordered koni srt.t shocks, struts and motorcraft gt500 strut mounts. I'm thinking about the about lowering kit when I install the shocks & struts. Has anyone installed this lowering kit on a convertible and if so how much did it lower it and how was the ride?

 

[JBert]

I have the P springs on my 2010 GT, with Bilstein struts/shocks. I think the convertible is just a little heavier, so it might drop a hair more, but might not be able to tell the difference.

I did not measure the drop (dumba$$) but it was similar to my previous Steeda Sport springs, meaning roughly an inch. I would have liked a little more drop in the front, right now the front is riding a little high, compared to the rear. Honestly I am not crazy about the ride ... I like it firm, but this is a bit "twitchy" or "jittery." It feels like maybe the struts/shocks don't have enough damping, but that should not be the case with new Bilsteins. It might be the progressive springs allowing some initial soft travel, then stiffening up quickly. It is hard to describe, but I think I liked the Steeda Sport springs better; they were also firm but I don't remember them feeling "jittery" like this. It might also have to do with other changes I made at the same time (hard bushings everywhere and a lot of camber) and it is hard to compare directly.

If I were in your shoes, I would take a look at the Steeda Sport springs also. They are well matched to the Koni STR-T's. I think they might have a version for the convertible, and they used to have a linear and a progressive version. I think I prefer the linear springs. Someday I might put the Steeda's back on my car to confirm whether I really do like them better, or if I'm just imagining it.

 

[Bamarider]

Thanks for the reply. I'll look into the steeds springs.

 

[SVT Rider]

Ford Racing Performance Springs (Like what JBert and I have on our vehicles):
M5300P - 1" Drop
M5300K - 1.5-1.7" Drop

The less lowering on the P springs is almost always better than the K, unless you are just going for looks. I have the K-springs which I use on the track and often wish it were the P-springs version, as the spring rate bias up front is better and more motion before bottoming out on all 4 corners of the vehicle.

Here's some more info for your decision process (click the links for some good discussion):

Factory Suspension Specs:
Factory (2005-2009)GT springs (Tags= Yellow, Orange) - front: 136lb/in / rear: 142lb/in

Aftermarket Performance Specs:
Eibach Pro-kit (pn 35101.140) / Ford Racing (K-springs) (pn M-5300-K) 1.5/1.7 - both variable front: 173-248lb/in / rear: 195-236lb/in
S197 GT Spring Rates and Heights (no guessing allowed) - MustangForums.com

Mustang GT (2011+) Stock: Ft 122 lbs./in Rr 154 lbs./in * Source, Maximum Motorsports
FRPP K Springs: Ft. 188 lbs./in Rr 221 lbs./in *Vorshlag Tested
FRPP P Springs: Ft. 204 lbs./in Rr. 165 lbs./in *Vorshlag Tested
302S: Ft 600lbs./in Rr 350lbs./in * Official Ford 302S manual
Spring Rates ???
Ford Racing Boss 302 Springs...
S197 Spring and Sway Bar Rates



The higher the spring rate, the more the stiffness of the ride is influenced (within reason depending on dampener)...the Koni Yellow struts and shocks will go a long way to making your ride enjoyable but firm...the SRT.T version are a decent road use version, from what I have heard but are non-adjustable.

 

[AndyEckel]

Nothing to add here except POST PICS WHEN DONE!