Great guide mate, nice one.
Regarding Turbo Starter, I am not sure if it is necessary to manually adjust the throttle. What I was doing was to just tap the screen on 3, 2, 1 *and* go, and it seems to put me into full throttle with boost active. I got the achievement this way, so it seems to count as a 'proper' boost start. Is a bit easier than having to worry about the throttle.
Many thanks to UK Dennis for this wonderful sig!