1. Stiffer engine mounts and tranny mounts lead to less movement which is better for the engine and tranny. If you have stock mounts get rid of them ASAP.
2. I've seen 3 types of Protege pistons myself. Held in my own hands, CP, Arias, and Wiseco. I've run 4 sets of Arias through my engine, so I changed to CP. The CP's blow everything else out of the water. I'm ashamed I didn't switch to them sooner. All the relief cuts are more precise and have beveled edges (leads to less potential hotspot area) and the forging looks to be of better quality. The Wiseco's are the worst of the three. Sharp edges, and like the Arias a domed piston top. My new CP's are flat topped. (Finally!) Not to say the Wiseco's are garbage, but they have no place in a "serious" build engine like this.
What LordWorm said is true, CP puts ALOT of R&D into their pistons, and have VERY strict quality control. They're quiet, well made, and strong as ****.
Before anyone flames MY OPINION remember, it is only MY OPINION. (Read that line again before you flame.)