Hey Carl,
Here's a couple options. If your running the Standard position with the linear springs. Try a Red center spring with 15k in the tubes and on the king pins.The red center spring brings back the steering.
I liked the progressive spring cause the car cornered alot better. Try this...
Associated gold side springs with blue center shock 15k in the tubes and king pin.Just watch out how much preload you use on the gold springs you just want it to touch the links. I used josh's Mod setup when I ran the standard position and the car was dialed!!!!
If the golds are to much for ya go with the blue side springs.
As for tires for 13.5 boosted stick with either a magenta front a pink rear or magentas all round. If you glue the front sidewalls, watch out how far up you put it up the side. If you go up way to far it will make the car push
I keep it around where the tire meets the rim area if that makes any sense Lol... Also try running some chassis rake 3.5mm front and 4mm rear.
As for body try CRC's Audi the closed cockpit one it rotates very well.If your running the AMR mount in 5mm forward it should help with alittle steering.
The Associated Black spring is the softest spring, roughly equal to the .18 Linear spring.
Yes i was looking at Josh's new rims when i get working again im going to order me some sets. I just recently got laid off Lol.... Dang Lol....I was planing on making a huge order to Lol....
Post your detailed setup and I can better help you as well.
If you have any more questions feel free to contact me.