In HK or China. There are only 2 class for touring. 5min and 8min. Most race no motor limit (it used to be 10.5T or something for stock (8min), as the turn out is so low they cancel the 10.5T limit). With the advance in Lipo tech all guys are running same car in 5 or 8min race. Same setup. Just the driving style is a little different as you don't want to over heat the tires in 8min race. lol BTW: For mod ( I am running 4.5T) I am using silverback 60C lipo. Usually I run 8.5min and the voltage afterward is around 3.6-3.7V pre cell.
If you really push it you can get 11-12 min run time . I think the voltage per cell is 3.1 or 3.2 after. Don't really wants to push it as it is so close to the 3.0V margin.