Using bricks to hold up cars is not a good idea...
Although unlikely, bricks are very brittle and can crack and split (or crumble). Yes, they are strong in compression, but any side loading can be disastrous.
One type of jack to avoid is the old fashioned stamped and welded sheet metal type. They are the type with bent sheet metal legs and a "strap" between each leg. If the spot welds let loose, the legs of the jack stand spread out and the car drops.
The Aluminum Torin jacks (seen on several threads on the forum, and the kind I used - and I first sow them in use in one of Randy's posts) are very strong. All the force is directed straight down through the post to the ground, not any legs. They are basically a post with a flat plate on the bottom to keep it vertical.
I have another type that looks somewhat like the old type, but it has a center post that goes to the ground. The three legs aren't really supporting the weight, they are providing stability.
In any case, when the Elise was sitting on top of my Torin Aluminum jack stands (with hockey pucks), the car was very stable.
One bit of advice when you use any type of jack stand - once you have the car in the air and before you remove the wheels, shake it. Although you don't want it to fall to the ground, it would be better if it happened with the wheels on and you not under it.