Putting some of the GT2 Parts on a T4 you will loose some setup options.
GT2 steering arms are very diff, bump steer is off.
Front A-arms at the c-hub shorten the wheel base a bit.
If you have replaced the #9580 washer with 4 #4187 washers you will lose this option
Front shock tower at turnbuckle mount is like one washer diff than a T4.
The only GT2 parts that I still have on my T4 is the front shock tower cause it is a bit more flexable so it may not brake as easy. BUT I have never broke a T4 front shock tower before!!!
Sometimes changing some front end parts will cause scuffing, draging one of the front tires. The "old" GT front was like that, just putting longer front axles on caused the inside front tire to scuff [drag], just something to think about.
Scuffing >>> more info here www.baysidehobby.com/forum/
You could asked the AE team guys at www.rc10b4.com
there is a T4 section.