I have purchased a pair of Brian Crower stage 2 cams 264 and BC valve springs & retainers . What I would like advice on is , would it be better to fit Nissan oem hydraulic lifters and rocker arms and new rocker arm shims . Rather than use the Nissan rocker arms and aftermarket hydraulic shims fitted just now ,less than 2k miles on them . Lastly where to get fitting rocker arm shims guide . Any advice appreciated