It would not be a bad idea to have this available - excessive exhaust temperature can wreak havoc with turbochargers, specifically with lubrication.
It might be possible to get a unit that takes all this information from the ECU OBD2 port and presents it (all of it, not just EGT) to you in any form you wish - dash mounted gauge, dash mounted TFT display for example. This would remove the need to add wiring and the need to 'corrupt' the exhaust system to mount an other sensor.
One thing to note, be very vigiliant and let your engine idle for a minute or two after swift driving. This allows the oil circulation to continue, thus bringing down the turbochargers internal temperature. Shutting down the engine immediately is a recipe for turbo failure. You might want to monitor oil temperature as well, for this very reason.