Can you hear the water moving around in saline? Can you feel the implant or does it feel like a normal boob?

Thank you for your question. In the right candidate, saline implants do feel very natural. After the initial healing period of time, you will not hear any noise from the implants. You would need to be examined or at least look at pictures to give you recommendations regarding a lift. 

 Generally patients don't complain of the sound or feel of saline moving around in the implant. Due to decrease viscosity they can feel somewhat unnatural particularly in very thin patients. Silicone gel is a better alternative in that circumstance. A modest amount of breast ptosis is easily camouflaged by breast augmentation without a breast lift.

will not slosh once healed but if you climb a mountain, you could hear noises above 8000 feet due to the pressure differential.  As for a lift, if your nipple is above a pencil placed under your breast at your fold, you do not need one.  If just below and you're willing to accept less than 'perfect' results, you could certainly just have your augment alone and see how they settle before committing to a breast lift.

If you have breasts that sag, implants alone usually do not do much except add volume.  A lift of some sort is often necessary.

An in person exam is needed to determine if you need a breast lift at the same setting as your breast augmentation.  Patients never complain about hearing water moving in the saline implants.  You may want to consider silicone gel implants for a natural look.  Consult with a Board Certified Plastic Surgeon to discuss your options and expectations.  Best to you!