Steven, I assume your sig is with the GC's/Yellows, that is about the height I am looking to go, maybe a touch higher in the back, so that would be fine with me.
I just want to know about the spring rate options, if it will be extra to get a custom rate.
I am definately a fan of the setup, just hoping to get a good deal on the GC's if it comes down to those.
Yeah my suspension setup is Koni/GC and on the sig picture I'm at 23.5" on 215/45-17. When I was on some 195/60-15 I use to be 23" from ground to fender.
I never asked them about custom rates, I forgot which site I ordered from, but they had the best deals around at the time. But if I had to do it again, custom spring rates would have been a plus in my books, but the Koni does give you the ability to adjust how soft/stiff you want it to be. But even with th default spring rate, so far I haven't bottomed out or have any type of shocks having contact of any sort.
You'll have that boat look if you set your GC sleeves the same for the front and back if you have them on the same perch, but to avoid that just adjust the perch from the fronts to the bottom perch and leave the rears on the top and have the sleeves set on the same thread. I'll give you pictures of before and after picture of how my car use to have a boat look and after I adjust the front perch of the Koni yellows.
Oh and you should be more than satisfied with the GC sleeves, but I would only pair them with Illumas, KYB AGX, or yellows. Some people have their own opinion, but of you want a full suspensions for about the same price, I'd get some Tien flex, FF type 2.5, or some AMR if you can find a member here that is selling theirs. But I paid about $970USD for my set up and is more than happy with what I can do with my suspension setup and how it rides.
Oh and I almost forgot, you're throwing in a bigger J motor, I don't know their comparison from weight, but I would rather have a higher rate in the front just to be on the safer side.
Edit: Some pictures.
Sorry this was the best picture I had of the car the day my suspensions were installed.
As you can see the front tires had about a good finger and 1/2 gap.
These were after I adjusted the Koni yellows in the front to get rid of that boat look. The front was lowered about a good 1/2".
Then my latest setup...