^GT and GTS have different plugs. GT is same as every toyota's harness from 1987 and up. there is no aftermarket harness for GTS. you'll have to get a diagram and cut them...
Shitty! I guess cause the stock amp. It complicates things. It seems to cause more trouble than its worth.
ABSOLUTELY NOT TRUE DON"T CUT!!!!!!
Go to www.cardomain.com
and then go to their store and search for head unit install stuff and go to wiring harnesses. For the GTS it's the 8-speaker one. It's very simple to use that wiring harness. And it comes with an amp interface for just using an aftermarket head unit with your stock amps so all your speakers are working properly. Any more questions PM me