Ok so whats the deal with 4volt preoutputs vs 2.5v -- can some one explain..?

tha other question for those that have replaced headunits and the new wired remote... Was the wired remote install pretty simple, how does it look in the same place as the crappy wired remotes that came in the 2007 lsv ... guess Im wanting to know if its going to look like a factory install job or an aftermarket job....?