Bought a truck, I have some upgrade questions

[Chevyguy317]

I recently bought a 2011 1500 Silverado and I want to do some modifications to it eventually, but I would like some advice for guys who know what they are talking about. 

 

1. Tonneau cover; 
             I am looking for a hard foldup cover for the truck. Any suggestions? I am looking into these two 

https://tonneaucoversworld.com/shop-...r-ax12008.html

https://bakindustries.com/bakflip-mx...silverado-1500

 

2. 3rd brake light;
             I have seen that a lot of the time the 3rd brake light gets water inside and starts to rust behind. I will be taking the light off tomorrow to check for rust, but what is the best way to seal it off?

 

3. Leveling kit;
             I looked at rough country, for $50 I could get a 2 inch leveling kit. Would you recommend some else?

 

4. Exhaust;
             I have no idea on this one. I want something my throaty but not something that is going to be a thousand bucks. 

Any help and suggestions would be awesome, thanks guys