the stock rear drums on a base Omni/rizon arent all that bad ; the front non-ventilated rotors are where I would start if I was upgrading
the website 'tryingbe' gave you will detail the "SLH" upgrades
for an Lbody, it also is possible to upgrade to "GLH/SC" level also altho that may actuall be more expensive than the SLH since GLH/SC hardware is relatively scarce ,,,