i think the comparison is a little off... to compare to the HR race i think you need to compare against the steeda super sport. these two are in the same catagorie essentially. the super race is HRs best, and Steeda competition. steeda sport and HR sport are on par.
of them its a toss up really. i think i am going to go with steeda supersport as i can get a better deal on them then i can the HR race, or i would be going with them.
The H&R spring rates are: front-950-1050 and rear-260-300.
Steeda does not list the rates (or I missed it) but based on their description, I'd say they are less based on the "ride quality not suffering". With 950 lb springs, your ride will definitely change!
The H&R springs will lower more too. I just ordered a set of H&Rs. I needed new springs for the IRS, and with the Ford C springs, my car still rides like my Grandmothers Caddy, plus it still looks a little "off roadish" to me.
I have had H&Rs on my 03 GT, but I was only running 740lbs and 275lbs, but the car was being used ofr Auto-X only. I thought they were great and the guy I sold them to now think they are pretty good as well.
Given I am now getting into road racing, I decided to go with the Maximum Motorsports Coilover conversion for front and rear, which come with hypercoil springs. I am now running 350lbs in front and 250lbs in the rear and the ride is great on the road and pretty darn good on the track as well.