RE: engine choice for pattern flying
I prefer 4 cycle, YS. It provides a greater control of speed during maneuvers than 2C. However, a few reasons to use 2C is cost of nitro in your location, economy, there are some inexpensive 2 cycles.
The fastest way to reduce noise it through 3 methods. First, an effective pipe arrangement. There are many at Central Hobbies. Second, a soft mount. Nothing compares to the Hyde mount for efficiency. Third, go to a multi blade prop.
Best of luck,