I've been reading on the topic and it seems that HRPs in Elite: Dangerous carry much more benefit than drawbacks. In most of my ships I have plenty of room for optional internal modules (like HRPs) so is there a reason not to buy them if I have the room to spare? Do they come with any other drawbacks apart from the worse maneuverability? I've seen a lot of builds on Coriolis where there are a lot of empty optional internal module slots and I don't really understand why.
Note that I'm doing bounty hunting and Combat Zone missions so things like jump range are irrelevant in my builds.
Best Answer
It depends. Personally, my combat ship has a couple Module and Hull Reinforcement Packages. However, my exploration/rat ship does not. The main thing to consider is whether you intend to get into combat, and whether you're willing to sacrifice some jump range. If the answer to both of these is yes, then it is probably a good idea to pick up some Hull or Module reinforcement. If you're looking to maximize jump range in a non-combat vessel however, then it might be better to skip it.
For a combat ship in particular, generally yes it is a good idea to fill space with reinforcement. Any downsides on maneuverability are fairly marginal, and unreinforced modules can usually be targeted and destroyed fairly quickly (though generally NPC pilots are not smart enough to do this).