Definitely go with heavier springs in the front. Seems those springs are 9.7lb in the front and 10.9lb in the rear????
I'm not very familiar with carpet setups but it seems you have too much steering going into the turns and stiffer springs will help that.
Another thought, can you adjust Dual Rate on your transmitter? I tend to turn mine down to 85% or so on an Airtronics M8. That helps me fine tune my steering input...