Long Post. 01 Mustang GT, originally had Bullitt springs with Bilstein shocks.
Changed over to H&R Sport Springs, reused the Bilsteins, new isolators all
around, and installed MM 4 bolt CC plates, 2 .5 inch spacers on top, both sides,
running Nitto 555 (stock size all around). Harsh ride, no suppleness at all,
every little irregularity in the road is fed back . :bang:

 

OOPs! 00 GT.

 

hmm.. have you checked to make sure your struts arent seized up somehow? the H&R's are a stiffer spring and are going to have a hader ride, but it shouldnt be so bad that it does that. You may need to check also into offset rack bushings for your steering.

Also i'm wondering if the way you put the spacers on the CC plates if you dont have it exact and its hitting the bump stop really easy in the struts.

 

Maximum Motorsports instructions said to use spacers on top of the
plate to equal the amount of drop of the spring, bit not so much as hit the
hood. Sports have a 1.5 inch drop, so one inch of spacers on top.
How do I determine if strut is seized, binding, or indeed hitting the internal
bumpstop? Thanks for replying.

 

go to each side of your car and push down. You should feel the strut compress and not really bottom out from you doing this. You may want to take it by your local 'stang shop (maybe hard on a rock in the middle of the ocean though) or somewhere that has a good rep for performance parts and have them take a look.

 

or if you take it to get it aligned (which you should do since you lowered it), the alignment guy should be able to give you a good solid opinion.

 

Try using the Saleen springs. I have them on my 02 GT and the ride is better than stock. My brother was so inpressed that we ordered the same spring and installed them on his 98 Cobra.