'Break in' is a loosely defined term. Some manufacturers tell you specifically how to treat your engine, some don't mention it. My dad's BMW 330 said to keep the RPM's below 4000 for the first 1200 miles. A general rule of thumb is to be nice to your engine for the first 1000 miles. Nice means no redline, you can drive fast, but don't stress the engine for the first 1000 miles. It's hard to do, especially with a brand new machine, but it's worth it. Keep in mind the engine is not the only thing that needs to break in, your brakes have a short wear in period of about 100-200 miles, and a lot of clutches also have a wear-in period, so you have to be careful for more reasons than you suspect.
It's best to follow the reccomended guidelines for oil changes. Unless you drive your car extremely hard (only use it for racing) or in horrible conditions (you live in the desert) the manufacturer's reccomended oil intervals are fine, if you're anal or have spare time, you can do it more often, it won't hurt anything. It is strongly reccomended that you leave the regular 'dino' oil in your car for the first oil change or two to let everything break in correctly. Once you hit 5000 miles or so all breaking in is done, and you can switch to a full synthetic. Mobil 1 is usually rated very well, is easy to find, and is not horribly expensive. Synthetic oils have fewer impurities in them than regular oils, resulting in a greater heat resistance, which makes them ideal for use in turbocharged engines which run hotter than NA engines. Do not mix oils. It's best to fill with an identical weight and brand for an oil change, every oil company uses different additives and competing additives can cause problems. NEVER mix dino oil and synthetic oil, or different weights of oil. Different weights and types of oil will separate inside your engine and become less efficient.
The main reason for a turbo timer is to prevent 'coking' which is the result of your turbocharger boiling off oil. This happens if the turbo is really hot and you shut off the engine, which stops the flow of oil, allowing what is inside the turbo bearings to boil off. When oil boils off it leaves carbon deposits behind called 'coke' which is very strong and coarce and not good to have on your turbo's bearings. This problem is less of an issue with synthetic oils as they have fewer impurities that can result in coke, but you still don't want to boil off a synthetic oil. A turbo timer will keep the engine running and the oil and coolant flowing through the turbo to cool it off and prevent this from happening. You can also just sit and idle your car for a couple minutes if you don't want to bother with a timer. Some of the really nice timers for the 1.8T like mine will actually monitor how you've been driving and vary the time the car continues to run based on how much you've heated up the turbo.
As for temperature, it doesn't matter, just make sure that as always, you let the engine properly warm up before you start to push it. Now I apologize for the huge response, I hope it's all clear, if not, let me know and I'll try to clarify.
. All the turbo timer does is keep the engine running after you turn off the ignition, remove the key, lock the door and walk away. They usually have some preset intervals (1min, 2min, 5min, etc.) plus you could program your own. The harder you were driving, the longer you set it for. Mazda actually only recommends a short cool-down period (30 or 60 seconds, I forget which.)
