For me, it is better to race on carpet.
Why? Because the grip levels are much higher usually than our outdoor tracks in the UK.
When you have grip, it is usually easier to find a good tyre and the setup is less important (providing the grip does not go up too much - and then you grip roll!)
Outdoors, you are changing setups when the grip comes up, (rear droop etc etc) which is something I never really got to grips with...
So, to answer you question I would decide first if you prefer outdoor or indoor racing, as it may help with your chassis choice.
Typically, a thicker chassis will help indoors to give it more of a response in it's cornering.
A thinner chassis can be better for outdoors, on a lower grip track where chassis flex can help the handling.