According the sticky, all front springs have the same spring rates. Obviously, the Z springs are a tad shorter and that has an effect on performance, but it seems only the rear springs on the G coupe and Z were stiffened for the sport models and revised?

Oem linear springs
G35 coupes with oem 17’s & 18’s
G35 sedan’s with sport suspension
350Z’s 2003/2004 (unrevised)
Front:314 Rear:342

Oem linear springs
G35 sedan's with non sport
Front: 283 Rear: 308

Oem linear springs
G35 coupes 2005/2006 with oem 19’s only
350Z 2004.5 to 2008 (revised suspension)
Front:314 Rear:427

 

yeah i think you are right.
to my knowledge increasing the rear spring rate while keeping the front the same increases oversteer in corners. So maybe the stock coupe was understeering a bit too much when driven hard. IMO the sport coupe oversteers a bit too much with the stiffer rear springs and the tiny 225 width tires, especially if you ditch the spare/tools/mats in back. Once I moved up to 245's in front it feels like it added back a good amount of understeer in the corners and I feel a bit more in control. At least I think this is how suspension works based on how it feels. I can't tell you what happens when you throw on swaybars and start adjusting them on top of spring and tire width changes.

I think there may be a "butt-chassis" phenomenon equivalent to the "butt-dyno" where I'm subjectively feeling differences that aren't there because I'm looking for them.

 

Thanks, I've been trying to figure out the best way to achieve a moderate drop while keeping the stock feel. I prefer a linear firm feeling.

The biggest issue is the cost and time of trying things out, undoing, buying more, putting it on, etc.

 

on a sport coupe with spacers and 19's I promise only you and the g-owners on this forum who live in georgia will know the difference between a moderate drop and stock. I think I am just going to do swaybars and call it a day. I will enjoy clearing speed bumps and not worrying about uneven tire wear until my stock shocks need replacing (then I'll drop 1inch front 0.6 inch rear b/c of mod bug).

 

True, I am spending a lot of time and money over something so minimal. But isn't that the way it usually goes

Thanks for the input.