How warm should my WRX be before I get into boost?

Watch oil temperature, not the coolant gauge. This is the single most useful thing to understand about warming up a turbocharged engine, and the dashboard actively encourages getting it wrong. Coolant reaches operating temperature relatively quickly, and the factory temperature gauge sits in its normal position long before the engine is genuinely warm. Oil takes considerably longer - often two to three times as long - because there is more of it, it sits further from the combustion chambers, and it has to circulate through the whole engine to come up to temperature. Oil is what protects bearings and turbo journals, and cold oil is thick, slow to reach where it is needed, and less able to maintain film strength under load. Boost applied to an engine with cold oil is where preventable wear happens. The practical target is around 180F oil temperature before you use boost properly. That figure is not arbitrary - oil cooler thermostats on this platform typically begin opening around 180F, which is a reasonable indication of when the oil is considered up to temperature. The right procedure is simpler than the forum rituals suggest. Start the car, give it ten to twenty seconds, then drive away gently. Extended stationary idling is not a good warm-up strategy - it heats the engine slowly and unevenly, wastes fuel, and on a cold morning it also makes you deeply unpopular with your neighbours given how loud the FA24 is on start-up. Driving gently warms everything faster and more evenly. Gently means low rpm, light throttle, and staying out of boost. You do not need to crawl. You need to not ask for full load. How long that takes depends on ambient temperature. On a mild day, ten minutes of normal driving is usually plenty. In genuine cold, it can take twenty minutes or more, and short winter trips may mean the oil never fully reaches temperature at all - which is exactly why cold-climate short-trip driving counts as severe service for oil change intervals. If you have an Accessport or any gauge that can display oil temperature, use it. It replaces all of this guesswork with a number. If you do not, a reasonable rule is to give it at least ten minutes of gentle driving in mild weather and considerably longer when it is cold. The same logic applies at the end of a hard drive. After sustained boost, a couple of minutes of gentle driving before shutdown lets the turbo shed heat with oil still circulating, rather than heat-soaking a stationary bearing.