Gauge Question

[YeA 20sF]

During the cold season down here (well not really cold just less time on the water at the moment) I would like to do most of the upgrades and changes on my 20SF before summer hits. One of the things on the to-do list is swaping out my current fugly guages to a full matching new set prossibly Livorsi or something. The question i have is are they really inboard or outboard specific ? I see lots of them on ebay and craigslist but its either just the gauge alone or a full set. Some ads say they are specific to outboard engines while other ads dont say much other than they are new items. What am I suppose to look for ? My boat dosent have a temp gauge so its somthing I need to add as well as swaping out the current PSi, RPM,volt and fuel for new ones. Help i'm a newbie to this stuff