One of the things the L3/L4 type cars don't have for an adjustment is the ability to run the RF suspension in the slightly trailing position like the more adjustable cars...I've seen some people slot the chassis mounting holes and countersink it all the way back to allow these adjustments.
I've also seen a couple with the SILVA rear pod setup installed to be able to put a little rear steer in.
I only run the L3's on a VELODROME...so it's doubtful that setup will help you.
On the L4, it's usually a green and or a red front spring, blue/silver on the rear w/ about 13.5 oz weight on the LR. This is for a flat 300+ ft. asphalt track...running 19t. on Foams.
3 Pink w/ a RF Double Purple for tires. (sometimes a magenta or double pink RR)