Me and my partner are into rough sex and I wear very tight tops. Are silicone breast implants more or less durable than saline?

You should be just fine. Breast implants are very durable and meant to withstand significant force/pressure.  In other words, much more significant traumatic force (than encountered during any type of athletic endeavor) would be necessary to cause a rupture. 
 My best advice: careful selection of board-certified plastic surgeon and careful communication of their goals.
Best wishes.

Hello! Thank you for your question! Altitude and pressure have no effect on breast implants, whether saline or silicone. It is safe to travel by air within pressurized cabins or even scuba dive without concern. No further precautions should be taken during these activities. Certainly, discuss any concerns with your surgeon prior. In the same manner, blunt force will unlikely cause rupture. Repeated trauma from the folding io the implant over time is known to be associated with rupture. Obviously, penetrating trauma from sharp objects will also result in rupture. Both saline and silicone implants are very durable and daily activities will likely not cause any increased risk to the integrity of the implant. Hope that thus helps. Best wishes!

The outer shell of both saline and silicone implants are highly durable. Neither implant will withstand a penetrating activities with erotic paraphernalia deeply introduced below the surface of the skin. Other erotic activities are definitely not an issue.