First thing i would suggest after this long time is to rebuild the car. Check for damage, replace worn out parts, bearings, etc ...
As long as its just about bashing around i would start with the electronics i have and then upgrade in this order:
-Lipo-Batteries and Charger (more power and much easier to handle IMO)
-Brushless-Combo (Xerun would be my choice as well for bashing)
-2,4 GHz Radio (not really necessary but it feels good to be up to date)
-faster servo if u feel like u need it (i´m using Savöx and i like it)
If u find out that u really want to start racing then IMO u should not spend to much money for upgrading this old chassis, but sell it and invest in a modern TC. There r some pretty good low-cost chassis available and for serious racing one of them would be the better choice. As said before in this case u should go to a local club and see what classes they run and what cars r popular there.
Hope this helps