springs for overweight CRT

[dirt101]

well I finally got to run my CRT on 5s today, and now im really pushing the limits with the stock springs. they are way to soft for my 10+lb brushless monster. What springs are you guys running in your truggies to get them stiffer?

on another note what center diff oil should I run? I would like it to be the thickest stuff I can run without it wheelying to bad. if it pulls the front tires up from a stop thats ok, but if it pulls them up at race pace then thats too thick for me.

Thanks!