As a child, my sister had G-pigs..some were noisy, others were not. As an adult, my SIL dumped one on us (multicolored longer sort of haired one with crazy cowlics...he was huge and named FatBoy!) My hubby and I had him in our small apartments. We had a cage meant for them (cage on top 2/3 with the solid plastic on the bottom tray part to keep the wood shavings in there). We came to love this fat little fella. He would do his sqwak whenever the refrig was opened..he wanted his fresh veggies! We always got the free parsley bunch offered at our grocery store with any other produce purchase...so he got that each week along with other items for a daily treat, in addition to his pellet food. If he got too noisy in the evening, we covered his cage with a light blanket/sheet and he settled down, but he really was only noisy when the refrigerated opened.
We babysat my nephews female G-pig when they went on vacation, knowing the repurcussions (sister said they would deal with babies)..and indeed, one baby boy came of the union (they literally come out of the Momma running..very strange!)...we decided to adopt him...once we knew he was a HE. We got a second identical cage and got a PVC tube and cut holes to connect the 2 cages. Worked great. My young niece named the new one "Little bit" as he was a little bit of the mommy and little bit of the daddy. He learned his daddies ways and made noise with the refridge. They were fun and interesting pets for the time we had them. We could hold them and they were not so fragile as a gerbil or hamster. If we let them run around, they did so in a covered blanket and we had to make sure they stayed in there (poo issues plus they would head to the walls and chew on cords!).
They like to hide, so give them something to hide under (we had a large fake wood tunnel)..they are like cavie animals...and ours loved parsley and carrots and apples and lettuce..just watch too much lettuce and they get poo issue and can harm them. Ours died from some weird virus, the vet said. Their insides got plugged up and they both died of it within 2 weeks of each other. Just a weird thing and we were really sad...we were attached to those silly little things. They were great apartment pets for us!