Pork (and chicken but that's another topic) is something I've learned to ALWAYS brine before cooking. Exceptions are the pork butt (shoulder) and ribs I use for "Q" ... not necessary 'cause of the long slow smoke cooking. (Although I've never tried BBQ'ing brined pork... so I'd be open to comments from anyone with that experience).
The pork I get here in my part of greater Seattle is quite flavorless and TOO lean... so soaking in a brine* (see below) solution for no less than 2 hours and typically no more than 8 hours (except for a whole pork loin that I brine for a day or more) adds/enhances the flavor and adds moisture.
The typical brine solution suggested by Cook's Illustrated is:
1 quart cool water
1/2 cup Diamond Crystal Kosher Salt
1/2 cup sugar
Mix in a non-reactive container until dissolved. Substitute 1/4 cup + 2 TBSP Morton Kosher Salt or 1/4 cup table salt for Diamond Crystal.
Make 1 quart of brine for each pound of meat, not to exceed 8 quarts (2 gallons). Soak meat for 1 hour per pound, but not less than 30 minutes or longer than 8 hours. If brining multiple pieces, base the brining time on the weight of an individual piece.
I don't actually do this
... I cheat on the amount of water (i.e. brine more than 1 lb of meat per quart) and cut down a bit on the salt... but that's to my taste.
Brining requires "osmosis" so you must have the salt and water.. I'm not sure "osmosis" needs sugar but at a minimum you need water and salt. A marinade won't penetrate as much without the "osmosis" action although you do get flavor from marinades.. and of course if your marinade includes enough salt, you probably get osmosis too?
Anyway, you can add other ingredients to the brine which include sugar, brown sugar, honey, molasses, maple syrup, fruit juices, beer, liquor, bay leaves, pickling spices, cloves, garlic, onion, chilies, citrus fruits, peppercorns, and other herbs and spices. Most recipes call for bringing the ingredients to a boil to dissolve the sugars and bring out the flavor of herbs, then cooling the mixture to below 40°F before use.
You might consider give brining a try next time you do some pork, by they chops or top loin or tenderloin, etc. I'll never go back to NOT brining unless I can get some good pork again.