I have a set of Ground Control coilovers on my EK and I'm trying to figure out what the spring rates are, since at the time I bought them I was young and didn't care as long as it lowered my car. Now I'm wanting to tune in my set up to handle better, but it makes it hard not knowing what I'm starting with.

The rear springs are marked "76633" and from my searching this also crosses to being a "GC180.64.44" which is 250 lb/in. However, the fronts are marked as either "71633" or "71632" (can't tell because the last number is worn a bit) and I can't get any results on either number from any online sources. However it doesn't seem to correspond to the default/basic spring rates that Eibach offers, so I'm wondering if it's a custom stiffer rate of some sort.

Any help is much appreciated!