You guys probably know what I am referring to- the plastic valve cover. Apparently, it is there to deaden some valve train noise. I took it off, went for a drive, and could not discern any difference in noise levels (I have a hardtop).
Does it trap heat? I have noticed that the Wrangler 3.6L gets much hotter than my 4Runner or Subaru. It also stays hotter for a much longer period of time while sitting in my garage after a drive. I'd like to just leave it off, if it is simply cosmetic. I'll put it back on if I go on some wet/muddy trails, I guess.