Here are some rates. I tried to get them out of h&r but they wouldn't give them up. These come from BMP.
50406 185F 340R
50404 118F 256R
The 50406's have stiffer rates to make up for the heavier 325 cars....about 300 lbs heavier than the 318 cars. 50404 =lower rates to drop the lighter 318 more.
It sounds to me that idealy, H&R should've reengineered a SHORTER spring for us rather than just taking the same length sport spring as the 325's and lightening up the spring rates. I wouldn't recommended those 50404's for any 318 other than someone that just wants the drop and a slight increase in handling.
I know the 29664's are supposed to drop the 318's more, but I don't get why they are even made? H&R should have just made a 50406 for both the 325/M3 with the listed spring rates and made the 50404 the same spring rates, only a slightly shorter spring to drop the 318 the same as the heavier 325/M3 cars.
