You should be able to use any tool chain that supports Cortex M4 processors.
The only problem could be how Paul's boot-loader works on Teensy 3.0. You need a hook to load you hex file.
The easy way is to use what ever Paul has packaged with his software. His stuff is always easy to use and reliable.
I am hoping to make ChibiOS a library for Teensy 3.0 using his tools. That way I can use his tools and have a RTOS.
I did that with the Arduino IDE for AVR processors.
I really like Freescale's documentation. Here is a good overview of true bare metal use of the device http://cache.freescale.com/files/32bit/doc/quick_ref_guide/KQRUG.pdf.