I've tried searching all morning, what exactly are the stock spring rates?

 

for the spyder anyway i mean.

 

or, how would springs with 13kg/m|727 lb/in front and 7kg/m|392 lb/in rears be?

 

I can't find the spring rates for the Spyder for some reason, but here's the other rates to get you in the ball park. Keep in mind the AWD spring rates are closest to yours since the weights are similar.
http://my.prostreetonline.com/forums...read.php?t=118
The rates you picked are pretty stiff for the front though. Are you looking to autocross your Spyder? If so, then the rears are soft, you'll have a loose backend.