I too will be racing my t4 on foams indoors on carpet, high grip.
+1 to the earlier suggestion - A diff up front is what I have got for mine.
You will also need to be looking at higher CST weights too, or the car will diff out.
Possibly harder springs and shock oils too to keep the suspension working less and grip rolling.
Droop will be important. I would possibly try none on the rear to start with and a minimal front setting.
Tyres, I will be using 42shore front, 40 shore front.
Hope that helps, but i cant tell you any more as im still building mine up!