Round the house, as in outside?
The T-Rex is not an in-the-house model. Oh, I do hover tests in my basement, but that is because she-who-must-be-obeyed has declared it my domain.
SE is fantastic if your budget is large enough. If not, the XL HDE or CDE are fine.
No upgrades needed. Just choose good components.
Align 430L and 35A ESC
Futaba gy401 gyro
4x hs56 servos
TP2100 3s LiPos

There are a lot of other servo choices that will also work.
There are many other batteries that will work.
There are better motors, but this is quite good performance at bottom dollar.
There is no reason to consider a gyro with less functionality.



(I know, the futaba gy240 is also rock solid and a bit cheaper, that will work too - just DON'T get a non head hold gyro)