I went to white/blue springs. up to 5mm on the front inner link. 4mm on the rear inner link and removed the .5mm roll center shims from under the rear blocks. went from an F block to a D block(2.5 rear toe) That was it, but I'm going to put my whole WE set-up on the car for Sunday. I even used the kit shock oil which I didn't mind. Just wanted to see how the box stock set-up performed.
As far as what it "needs" for carpet. I don't think it needs anything for handling purposes some say changing to the hard 46mm swingshafts make the spool outdrives last longer, the IFS c-hubs, some steel ball connectors instead of the aluminum. I don't hit too much so I just leave the stock stuff on and haven't had any issue's.
I would suggest getting some suspension blocks tho. 1D's for the front(widens it out for carpet) and a 1C, 1D, 1E for tuning the rear toe. The 3.5 degrees the stock set-up has is great for mod but overkill for anything else.
I have the split blocks as well but only plan to use them on asphalt.
here are some pics: