^Turbo timers are only really critical in oil-cooled turbos; we have coolant circulated through ours so not only do they have another fluid running through them, but the coolant flow rate is much, much higher than the oil flow rate, allowing for much more effective cooling in a short period of time. The only time you really wouldn't have sufficient time for it to cool would be if you did a lot of highway pulls and just shut the car off at the end of the last one before braking back down to a stop. Assuming you get off the highway and park after driving hard (or spend a minute or so going through a neighborhood or parking lot after some nice twisties etc), a turbo timer is unnecessary.
In addition, its going to be very difficult to install because of the communication between the microchip in your key and the ECU through the CAN; you'll basically need to leave a spare key somewhere right next to the key-hole, effectively disabling the security feature and allowing your car to be started by anyone's thumb.
Basically, slow down speed racer, take care of your car so that it'll take care of you, and don't put her away hot. Basic mechanical sympathy.
I assume this is the same coolant going through the engine, so the lower thermostat couldn't hurt, right? And much less hassle...Our turbos are oil and water cooled, it would be a waste. Put your money towards a tune. Drive it hard, park and go about your business. You have probably noticed how hot these engine bays get, your turbo will survive.
I'm the only 9-3 on this forum with a lower T-stat it looks like...I assume this is the same coolant going through the engine, so the lower thermostat couldn't hurt, right? And much less hassle...