My cam gears are rattling during engine warm up on my 92 N/A. I have searched about this and am going to replace the springs. Mine went 180K before they started to rattle. I have considered using the JWT heacy springs. My concern is that I read that JWT springs are so stiff that they eliminate the variableness of the cam and make it like a solid cam. I like the variable timing set up, so what is your opinion. Stock or JWT?