I've tested over 600 different products on this site and I have never found a product that improved agility.
The only thing I've tried that didn't work is the tarp. It is a good idea to keep a small tarp at all times and use it as a shelter if you're going on longer hikes. The tarp should be put away when you get back to camp or to your car, because it won't help in an emergency. There is a great video of a guy who was climbing with his dog, in this clip you can see the dog trying to hide, in the end he had to run away. This is an important point. You will be more likely to get stuck on the trail if you don't have a tarp. If you're going for a long hike you should leave your tent at home. You can still use a tarp on a long hike, and it can keep you warm if you find yourself in the wind. A lot of hikers are tempted to put on their sleeping bags, pack them up, and go for the trail. This is probably a bad idea, because it will take you farther out. Don't worry if your bag is heavy. It's all about how you use it.