how does a boost controller work?
how does a turbo timer work? and what does it do?

A boost controller limits when the wastegate actuator sees boost. The wastegate is what vents exhaust gases from the exhaust before the turbo to prevent the turbo from spooling up more and creating more boost. Manual boost controllers are simply a ball and spring, the more tension on that ball the more boost pressure it will take to bypass that ball to get to the wastegate actuator to stop making boost. Electronic boost controllers use a pressure sensor and a solenoid controlled by a small computer.

Turbo timers are nothing more than a stopwatch to keep your car running after driving it. It allows you to park your car, lock the doors and walk away while letting your car run a few minutes longer to allow to turbo to cool. If you run your car hard and shut the engine off without letting it cool down the oil will literally bake inside the turbo, in turn ruining the bushings/bearings much more quickly than if it were treated properly.

basically a small pneumatic pressure regulator which air then forces the acuator to move the flapper vavle in the exhaust housing to open

the lighter the spring tension, when boost flows into that part of the system, the air pushes the spring and ball deal so air can pass through the controller and to the acuator and move the flapper valve, thus the more spring tension set on the mbc, the more boost it will take to pop the valve open, and opening the vavle and thus making the boost rise.

i guess you can say its similar to adjustable blowoff valves, but used for a different purpose..

It is wired into some of the ignition wires and keeps the car running when you park, usually for no good reason.

It makes companies like Greddy and HKS a lot of money.

so would you need a turbo timer? or is it a wasted of money?

i have one because im lazy and dont feel like waiting in my car, plus it came with the car

I personally think it's a waste of money, but a lot of people use them. It isn't all that needed on a water cooled turbo. And you only need to run it if you immediately shut the car off after boosting it a lot, like doing a 1/4 mile run then shutting it off in the pits right away. If you were boosting some on the highway then you drove a mile on the streets by your house normally and parked the car then there is no need to run the turbo timer. If you do run it, then you are probably going start heating the turbo more than it originally was with hot coolant from idling too long with no air flow to the radiator. They do work good for warming your car up in the cold though, set it for 10 mins take the keys and go back inside for a while.

i guess it'll be pretty usefull in minnesota winters, but i dont think i would drive my dsm in the winter.