you can get the gt2 in rtr or factory team kit version....the kit is a much better truck, it comes with all the hop up optional parts in the kit...check the b/s/t forum there are many of them for sale with good prices...
with the ft kit there is no real need to make any upgrades....
the ae smoothy pipe is the best pipe for the gt2 IMO...
as for the firestorm, im sure its an ok truck, but to really compete you should run either the ae gt2 or the losi ad2...